Environmentally Friendly Plant Terpenoids and Their Biological Activity

Abstract

This chapter is devoted to the phytochemical study of sesquiterpene lactones of some plants of the Asteraceae family and their biological activity. At the same time, the effective growth activity of sesquiterpene lactones isolated by us from plants of the genus Artemisia was established, which improves the quality and increases the yield of rice, cotton and the productivity of mulberry cocoons. Also, a clear mutagenic, anti-nosema, antiviral and insecticidal activity of the amount of lactones isolated from plants of the genus Centaurea, Acroptilon and Handelia was revealed. A technology has been developed for obtaining biologically active compounds from plant materials and methods for the quantitative and qualitative determination of sesquiterpene lactones in plant materials and extracts.

1. Introduction

The plant flora of Uzbekistan is very diverse and rich. From 8000 thousand species growing in Central Asia, it is represented by more than 4500 plant species. The basis of the flora of Uzbekistan is 10 large families: Asteraceae, Fabaceae, Poaceae, Brassicaceae, Rosaceae, Lamiaceae, Chenopodiaceae, Carophyllaceae, Liliaceae, Boraginaceae. At present, scientists of Uzbekistan have established groups of wild plants of natural flora for their use in medicine (600 species), food industry (400 species), essential oil (600 species), alkaloid-containing, glycoside-containing, coumarin-containing, flavonoid, terpenoid (3500 species), saponin-bearing 100 species, tanning 400 species, vitamin-bearing 600 species, fodder 1700 species.

Plants of family Asteraceae for wide application are easily available and widely distributed in the territory of our republic. Currently, medicine and agriculture mainly use synthetic preparations that are toxic and pollute the environment, while preparations based on plant materials do not have toxicity, but have a wide range of biological effects, and are environmentally friendly to humans, animals and the environment. However, in recent years, these plants have been severely exterminated and innovative research in this direction is not carried out to the full extent. In this regard, consistent reforms are being implemented in the republic for the protection of medicinal plants and their processing, conditions are being created to increase the export potential of the industry, as well as the integration of education, science and production processes.

In order to find and introduce new highly effective preparations and pesticides, it is necessary to expand the development of methods for obtaining biologically active compounds from wild and medicinal plants.

Sesquiterpene lactones, being a large group of secondary metabolites, are widely distributed in plants, and more than 5000 of their representatives with mono-, di- and tricyclic carbon skeletons have been isolated and established [1, 2].

2. Materials and methods of the research

The object of the research are widespread plants of the genus Artemisia, Centaurea and Handelia, family Asteraceae.

2.1 Research methods

Phytochemical, technological, physicochemical, biological.

Phytochemical and technological methods are used to develop the optimal technology for obtaining individual sesquiterpene lactones and the total lactones from plant materials (extraction of organic solvents, purification from ballast substances, separation by polarity and chromatographic separation, technological scheme for the isolation of biologically active compounds).

Physical and chemical methods - Infrared spectroscopy (IR), Ultraviolet spectroscopy (UFS), High performance liquid chromatography (HPLC) analyzes the completeness of the extraction of biologically active compounds (BAS) from plant materials, step-by-step control of technological processes of obtaining, determination of the qualitative and quantitative composition of biologically active substances (BAS) and identification of isolated compounds.

Biological methods determine the biostimulating, mutagenic, antiparasitic and insecticidal activity of the developed preparations.

2.2 Growth activity of rice growing and cotton growing

The objects of the study were widely distributed in Uzbekistan plants belonging to the Asteraceae family: Artemisia tenuisecta Nevski., Artemisia sogdiana Bunge., Artemisia leucodes Schrenk. and Artemisia absinthium L., producing active terpenoids, in particular sesquiterpene lactones α- and β-santonins, leukomizin, austricin, which have growth-stimulating activity.

Rice is the most common cereal crop in the world. It is a dietary product, has high nutritional properties, contains 70–80% starch and 7–8% protein, the latter being characterized by exceptionally high digestibility and a favorable balanced content of essential amino acids.

In terms of yield, rice ranks first among grain crops, and in terms of sown area and gross grain harvest, it ranks second.

To obtain high and stable yields of agricultural crops, it is necessary to introduce highly effective plant growth regulators that meet modern technology and environmental requirements. The need to use growth regulators in rice sowing is associated with low field germination of seeds, high empty grain of the panicle and lodging of the rice crop. There are various ways to regulate the growth and development of agricultural crops using natural and synthetic biologically active substances, such as auxins, gibberellins, cytokinins, etc. [3]. However, some of these substances are expensive, while others have not been widely used due to insufficient stability or relatively high toxicity (for example, auxins). Therefore, the task of creating and using cheap, non-toxic natural preparations that act, like phytohormones, in ultra-low concentrations, is relevant today. This task is also relevant for the cultivation of rice, since rice is one of the main food products of the inhabitants of the countries of Southeast Asia, including Uzbekistan, since the use of plant growth biostimulants during presowing seed treatment and spraying of rice crops makes it possible to increase the energy of seed germination, to obtain fast and friendly shoots, increase the development of the root system and plant biomass by 10%, leaf surface area and chlorophyll content, increase productivity.

The use of plant growth regulators with a versatile spectrum of action contributes to a significant reduction in the use of plant protection products against diseases and pests. Therefore, an integrated approach to the use of plant growth bioregulators, which have both growth-regulating and immunostimulating effects in the system of other technology elements, is still relevant at the present time.

To date, as a result of the studies, one of the effective biostimulants for increasing the yield of rice are natural sesquiterpenoids α-santonin, zerumbon and C₁₆-guayanolide, isolated from various plants, increase the yield of rice after one-day soaking of seeds in their solutions at a dilution of 1:10000 compared with control at 14.17% (santonin, zerumbon) and 7.5% (C₁₆-guayanolide) [4, 5].

Our research in recent years found that the plants of the family Asteraceae of the flora of Uzbekistan are rich sources of biologically active sesquiterpenoids. For example, the aforementioned α-santonin, which is used in India as a biostimulant to increase the yield of rice, is produced in major quantities by plants of the genus Artemisia which are grown in Uzbekistan. These types of wormwood are the main edificators of plant communities in the arid and semi-arid zones of Uzbekistan and form wormwood pastures over a vast territory, and which can be used as a raw material for the production of α-santonin in the required quantities for its use as a growth stimulant.

We also considered the growth-regulating activity of a number of sesquiterpenoids liganolide, repin, granilin and artabine, including α-santonin, which we isolated from plants of the flora of Uzbekistan (Figure 1). Some of the results of these studies were published by the authors in the open press [6, 7].

Figure 1.

Structural formulae of lactones with biostimulating activity.

An effective method of using plant growth and development regulators is the pre-sowing seed lock. The following methodology was used to consider the growth of stimulating activity. They took an exact weight of the terpenoid, dissolved it in a small amount of alcohol, and diluted it with warm water to a volume in a ratio of 1:10000. Then, rice seeds of the Iskandar variety were immersed in the resulting solution of each terpenoid for 24 hours separately. The treated seeds were planted on experimental small plots row by row at a distance of 15 cm.

The yield was determined by dry weight and the results were compared with the control. As the results showed, the most active growth regulators were α-santonin, liganolide, repin, leucomizin, which significantly increased the yield of rice by an average of 12.5%, and granilin and artabine - up to 10%.

According to the list of pesticides and agrochemicals permitted for use in agriculture of the Republic of Uzbekistan, published in the collection (Tashkent, 2013), rice growth regulator “Edagum SM” (LLC “Spetsesnaska M Service”, imported from Russia) is noted in our Republic used [8].

The main disadvantage of the Edagum SM biostimulant is the laboriousness of its use, which consists in the repeated processing of rice during the growing season to increase yields, which is not economically viable.

In this regard, we have been conducting research for a number of years in order to find and create a cost-effective, effective stimulant that increases the yield of rice.

As a result of ongoing research, a natural sesquiterpenoid 2-keto-8α-hydroxy-5α, 6β, 7α, 11β (H)-guai-1(10), 3-diene-6,10-olide monohydrate (1). The source of this sesquiterpenoid is wormwood from the subgenus Seriphidium, widely distributed in Uzbekistan.

The growth-regulating properties of this sesquiterpenoid, which we called the preparation “Risolid”, can effectively increase the yield of rice with a single pre-sowing treatment of rice. Below are the results of biological studies of compound 1.

As can be seen from the data in Table 1, this biostimulant has a great influence on the germination of rice seeds.

№	Experiment options	Number of germinated plants per 1 m^2 of area, pieces	Seed germination, %	Plant growth, cm
1	Control	256	51.2	10.5
2	Risolid 50 g/t seeds	281	56.2	11.5
3	Risolid 75 g/t seeds	279	55.9	11.2
4	Risolid 100 g/t seeds	280	55.7	10.8
5	125 g/t seeds	261	53.0	10.7
	Coef. Student R		2.7	0.05

Table 1.

Determination of seed germination in the field.

Based on the analyzes, it can be seen that in the control variant, the growth of plants was 127 cm, the length of the panicle was 25.3 cm, the weight of the main panicle was 1.8 g, the weight of the lateral panicle was 0.8 g, and the yield was 55.9 centners per hectare. In the 2nd variant of the experiment (Edagum SM preparation), the plant growth was 132 cm, the length of the panicle was 27.8 cm, the weight of the main panicle was 1.8 cm, the weight of the lateral panicle was 0.9 g, the yield was 65.4 centners, which was 9.6 centners higher compared to control. In 3–4 variants of field experiments (Risolid preparation 50 and 75 g/t of seeds), plant growth was 135–136 cm, panicle length – 27.8–27.9 cm, main panicle weight 2.2 cm, lateral panicle weight 1 0–1.1 g, the yield was 70.3–70.4 centners, which was 14.4–14.5 centners higher compared to the control (see Table 2). Table 2 shows the rice yield indicators. Tashkent region, Srednechirchik district NIIR 2022.

№	Experiment options	Number of plants in 1 m^2, pieces	Bushing degree	Plant growth, cm	Panicle length, cm	Grain weight of one panicle, (average), g		Weight 1000 pcs. Grain, g	Biological yield, g	Real yield, c/ha
						Main panicle	Lateral panicle
1	Control	240	1.12	127	25.3	1.8	0.8	28.9	698	55.9
2	Edagum SM	255	1.13	132	27.8	1.8	0.9	32.1	864	65.4
3	Risolid 50 g/t seeds	262	1.12	135	27.9	2.2	1.0	33.3	880	70.4
4	Risolid 75 g/t seeds	262	1.12	136	28.0	2.2	1.1	33.2	879	70.3
5	Risolid 100 g/t seeds	258	1.10	137	26.7	2.2	0.8	32.9	851	69.1
6	Risolid 125 g/t seeds	254	1.13	130	27.5	1.9	09	315	803	68.3

Table 2.

The results of field trials of the preparation Risolid in comparison with the prototype Edagum SM.

Note: Tashkent region, Srednechirchik district RRI 2022.

The results of the tests indicate that the proposed preparation Risolid has a high growth-regulating activity at low concentrations, which leads to an increase in the yield of rice, and, thus, this agent can be used in agriculture to increase the yield of rice.

By studying the IR and HPLC of the isolated sesquiterpene lactones, their identification was carried out, the purity of the samples was established, and the quantitative and qualitative content of α-santonin, β-santonin, leukomisin and austricin in plant raw materials and extracts was determined using the HPLC method.

Ionizing radiation and chemical mutagens are mainly used in the selection of initial material in cotton growing. The use of mutagens of plant origin makes it possible to obtain valuable source material for breeding purposes in a short time.

Earlier, when studying the mutant effect of extractive substances Artemisia absinthium (preparation “PRP”) on cotton, we obtained mutant lines. It was found that at various concentrations PRP has a pronounced biostimulating and mutagenic activity. Cotton seeds of varieties C-6524, C-6532, C-9070, etc. were treated with a preparation of various concentrations (2.0; 1.5; 1.0; 0.5%) and sown in the field. The following indicators were analyzed: seed germination, plant survival and the degree of development of traits characterizing productivity. In experimental variants at concentrations of 1.0 and 0.5%, there is a pronounced stimulation, in particular, the accumulation of fruit organs on a bush, an increase in the weight of raw cotton per plant, due to an increase in the number and weight of bolls [9, 10, 11].

This preparation at concentrations of 2 and 1% was used as a modifier to relieve depression during seed irradiation. For the study, the C-6524 variety was taken, as mutagenic factors—Co⁶⁰ gamma rays and the PRP preparation at a concentration of 1 and 0.5%. Non-irradiated seeds, simply soaked in water, served as the control, and the second control was simply irradiated seeds.

As a result of the research, promising breeding material was obtained in the form of mutant lines and varieties. A number of promising mutant lines are being studied in the laboratory and nurseries ermacron mutagenesis. Two mutant lines are tested in competitive and station variety trials. Since the polar sum of wormwood showed biostimulating activity, in order to isolate the active principle, we studied the chemical composition of the aqueous extract of the aerial part of the raw material. A new water-soluble sesquiterpene lactone (I) of composition С₁₅Н₂₂О₅ was isolated by chromatographic separation method, m.p.164-165°C. The IR spectrum acetyl derivative showed absorption bands at 3440 cm⁻¹ characteristic of the tertiary hydroxyl group. The formation of this product confirms the presence of a secondary hydroxyl.

Oxidation of 1 with chromium (6) oxide gave keto derivative 3 with mp 183–184°C. The keto derivative 3 is identical in physicochemical constants and spectral data to the lactone artabsinolide B. Therefore, the new lactone 1 is an epimer of artabsinolide C [12]. Based on the above results, it can be concluded that the isolation and study of Artemisia absinthium terpenoids will lead to the creation of biostimulants for use in cotton growing.

2.3 Antinosema and antiviral activity in sericulture

On a global scale, the production of live cocoons is growing, along with this, due to dangerous infectious diseases, 15–20% of the cocoon crop is damaged. There is evidence that the sources of antibacterial, antiviral, antiprotozoal agents are medicinal plants containing various classes of natural compounds (alkaloids, quinones, polyphenols, saponins, terpenoids, sesquiterpene lactones) [13, 14].

The aim of our research was to test extracts (total sesquiterpene lactones) isolated from various plants against silkworm nosematosis.

After processing grena with agents representing the sum of sesquiterpene lactones Artemisia tenuisecta (ATEN), Artemisia annua (AANN), Acroptilon repens (AREP), Centaurea squarrosa (CESK) only in the variant 4, a decrease in the output of caterpillars was observed compared to the control by an average of 8.25%. In other variants, the revitalization of grena was higher than in the control and ranged from 81.5–89.0%. It is obvious that the revival of grena is to a certain extent dependent on the means used. The higher the concentration of the agent, the lower the percentage of caterpillar yield (Table 3).

№ вар	Symbol of the agent and concentration,%	Grena revitalization after processing, %			In comparison with the control
					Increase	Decrease
		$\overline{X}$ ± S $\overline{x}$	Cv	Рd	abs. %	abs. %
1	I (0.5%)	84.7 ± 0.20	0.4	0.999	4.50	—
2	I (1.0%)	81.5 ± 0.32	0.7	0.999	1.25	—
3	II (0.5%)	85.5 ± 0.45	0.4	0.999	5.25	—
4	II (1.0)	72.0 ± 0.32	0.8	0.999	—	8.25
5	IV (0.5%)	89.0 ± 0.76	1.5	0.999	8.75	—
6	III (0.5%)	81.5 ± 0.26	0.3	0.999	1.25	—
7	IV + III + I + II(0.5% each)	82.0 ± 0.08	0.1	0.999	1.75	—
8	Control (water)	80.25 ± 0.46	1.0

Table 3.

Revitalization of grena after treatment with the amount of lactones of different concentrations.

Higher concentrations of solutions of the studied agents, as in medicine with pharmaceuticals, had a depressing effect on a living organism—silkworm grena. In cases using higher concentrations of extracts (2, 4), a slight increase in revitalization (ATEN 1.0–1.25%) or a serious decrease (AANN 1.0–8.25%) was recorded. In variants (1, 3, 5), where grena was treated in solutions of agents with a lower concentration, an increase in the yield of caterpillars (revitalization) by 4.50–8.75 absolute percent was observed. Under grena production conditions, this is a rather high percentage, indicating a significant increase in the quality of grena.

In the same experiment, another, much more important indicator of the quality of grena was taken into account—its infection with nosematosis, or rather, the decrease in infection under the influence of tested agents.

Table 4 presents the results of infestation of caterpillars after grena treatment in solutions of sesquiterpene lactones.

№	Symbol of the agent and concentration,%	Infection of caterpillars-animators, %	Decrease in infection compared to control
			abs. %	rel. %
1	I (0.5%)	4.5	3.6	44.4
2	I (1.0%)	1.8	6.3	77.8
3	II (0.5%)	3.2	4.9	60.5
4	II (1.0)	2.4	5.7	70.4
5	IV (0.5%)	0.9	7.2	88.9
6	III (0.5%)	2.6	5.5	67.9
7	IV + III + I + II (0.5% each)	2.4	5.7	70.4
8	Control (water)	8.1	—	—

Table 4.

Infection of caterpillars with nosematosis after treatment with the amount of sesquiterpene lactones of different concentrations.

Analysis of the obtained results presented in Table 4 indicates that after the treatment of nosematosis-infected grena with solutions of the sum of sesquiterpene lactones, infection with nosematosis in hatched caterpillars decreased in all variants. Each caterpillar emerging from the treated grena was microscopically examined individually. Treatment with solutions of extracts of grena infected with nosematosis reduced the infection of emerging caterpillars by 3.6–7.2% absolute, or by 44.4–88.9 relative percent, compared with the control. The most effective, having a high anti-nositogenic effect, were agents with the code names CESK at 0.5% concentration, ATEN at 1.0% concentration and AANN at 1.0% concentration.

These funds are isolated from wormwood finely dissected, wormwood annual and cornflower splayed and have antihelminthic, antiprotozoal, antimalarial, as well as anti-inflammatory and immunostimulating properties. The causative agent of silkworm nosematosis, located in grena, belongs to the group of protozoal insect diseases. The results obtained by reducing the infection of caterpillars with nosematosis testify to the active effect of the amount of sesquiterpene lactones on the causative agent of the protozoan disease of the silkworm. An increase in the yield of caterpillars from grena treated with the above preparations indicates the immunostimulating effect of the tested agents.

The results obtained on the influence of the amount of sesquiterpene lactones on the infection of grena with nosematosis were processed by a mathematical method. Mathematical processing of the results of the experiment on the revitalization of grena and on the infection of revivalists caterpillars with nosematosis testifies to their reliability.

For clarity, we present the infection of revival caterpillars with silkworm nosematosis, hatched from grena, slightly infected with nosematosis and treated with herbal preparations (Figure 2).

Figure 2.

Infection with nosematosis in revival caterpillars emerging from slightly infected and treated preparations of grena.

As can be seen in Figure 2, the lowest infection with nosematosis is observed in revival caterpillars that emerged from a slightly infected grena treated with CESK (0.9%), ATEN 1.0 (1.8%), AANN 1.0 (2.4%). It should be noted that the use of plant biostimulants in high concentrations of ATEN 1.0 and AANN 1.0 caused a decrease in the revitalization of grena within the experiment, that is, it had a depressing effect on the development of the embryo (Table 3). The same terpenoids caused a decrease in the infestation of caterpillars-animators by 6.3 and 5.7 absolute or 77.8 and 70.4 relative percent, respectively (Table 4). Consequently, sesquiterpene lactones have a detrimental effect on silkworm nosematosis, while simultaneously suppressing biochemical processes in the body of the spore host.

Among the diseases of the silkworm, the most dangerous is also the viral disease nuclear polyhedrosis (jaundice). If this disease occurs on the rearing of the silkworm, then it is practically impossible to obtain any harvest of silk cocoons.

At present, there are no radical methods of combating this disease in Uzbekistan and neighboring countries, and sericulture suffers great material losses.

To solve this problem, in order to reduce the occurrence of spontaneous jaundice on silkworm rearings, terpenoids produced by the aerial part of Artemisia tenuisecta and A. leucodes are proposed, which have high antiviral activity and are able to inhibit the transition of the latent jaundice virus to the active state [15].

To be able to introduce funds based on sesquiterpenoids, the method of obtaining individual sesquiterpene lactones from plants of the flora of Uzbekistan, their subsequent alkaline hydrolysis is expensive, in this regard, the use of extractive amounts of sesquiterpene lactones converted into a water-soluble form by alkaline hydrolysis reduces the cost of the final product several times. In order to improve the quality of grena and the yield of mulberry cocoons, water-soluble extractive amounts of sesquiterpene lactones of three types of the aerial parts of plants of the flora of Uzbekistan were used: Artemisia annua L. (annual wormwood), Artemisia tenuisecta Nevski, Artemisia leucodes Schrenk (whitish wormwood).

The sum of sesquiterpenoids of the aerial part of Artemisia leucodes Schrenk contains: leukomizin (1), austricin (2), matrikarin (5), parishin B (6), parishin C (7), artelin (8), artelein (9), anhydroaustricin (10). It was previously established that the extractive sum of sesquiterpenoids, as well as individual lactones, exhibit antiprotozoal, choleretic and antiviral activities.

The aerial part of Artemisia tenuisecta Nevski contains mainly santonin (4), which is used as an anthelmintic.

The extractive sum of the aerial part of Artemisia annua L. contains sesquiterpene lactones arteannuin B (3), artemisinin (16), arteannuins H (17), K (18), L (19), M (20), 11,13-dihydroarteannuin B (21) and artemisinic acid (22) and exhibits bactericidal activity, inhibits the growth of the anthrax pathogen, the decoction is used as an anthelmintic, for respiratory infections, jaundice, skin diseases, malaria, tumors.

The above plants were collected during the period of budding and the beginning of flowering with the maximum content of sesquiterpene lactones in the Fergana and Tashkent regions.

As a result of the research, it was found that the created agent “ALEU” has biological activity that can inhibit the transition of the latent jaundice virus to the active state, that is, slow down the development of the disease. As a result of the treatment of grena with this preparation, there is an increase in revitalization by 3.4%, and viability increases by 5.8–8.0%. Accordingly, such caterpillars curl larger cocoons, with a mass of 0.11–0.15 g higher than that of caterpillars that emerged from untreated grain. The yield of cocoons from one box of grena increases by 3.6–4.1 kg.

Means “ALEU” is the amount of lactones isolated from plants of the domestic flora and is environmentally friendly to humans, animals and the environment.

The products of alkaline hydrolysis of sesquiterpene lactones leukomizin (1), austricin (2), arteannuin B (3), α-santonin (4) and their antiviral activity against the latent silkworm nuclear polyhedrosis virus were also studied.

Aqueous solutions of hydrolysis products of leucomizin, austricin, arteannuin B, and α-santonin were tested on silkworm grena, susceptible to latent nuclear polyhedrosis virus. The results of the experiment are presented in Table 5.

Products of hydrolysis of lactones	Leucomizin (1)		Austricine (2)		Arteannuin B (3)		Santonin (4)		Water Control
Solution concentration (%)	0.5	0.1	0.5	0.1	0.5	0.1	0.5	0.1	—
The exit of the caterpillars from the processed grena (revitalization of the grena)	94.8	96.2	96.6	94.8	95.0	96.1	97.6	95.8	95.5
Total % death due to induction of the YP virus	27.1	30.7	32.8	23.8	28.9	35.5	30.2	32.0	43.4
Increase in viability compared to control (%)	16.3	12.7	10.6	19.6	14.5	7.9	13.2	11.3	—

Table 5.

Influence of alkaline hydrolysis products of sesquiterpene lactones on grena vitality and viability of silkworm.

The data in the table show an increase in the revival of grena in most of the experimental options by 0.3–2.1% compared to the control option. In addition, in all experimental variants, the death of caterpillars from the induction of nuclear polyhedrosis, relative to the control, decreases and the viability of the silkworm increases after the induction of the nuclear polyhedrosis virus from 2.5 to 19.6%.

Thus, the tests carried out indicate a positive effect of the products of alkaline hydrolysis of sesquiterpene lactones leucomizin (1), austricin (2), arteannuin B (3) and α-santonin (4) on the revitalization of grena and the viability of the silkworm to the disease of nuclear polyhedrosis, which depends on the concentration of the solution and the structure of the studied lactones.

We have studied the effect of the extractive sum of sesquiterpene lactones (SPG) from the herb wormwood (Artemisia absinthium) on the productive and reproductive properties of the silkworm, since we have previously isolated biologically active sesquiterpene lactones from this plant. Testing aqueous solutions of the amount of wormwood lactones (0.1–0.25%) leads to an increase in the productivity of the silkworm, which is expressed in an increase in silkiness by 3.1% and yield by 20%.

Thus, it becomes clear that when using biostimulants, one should be careful when choosing preparation concentrations in order to maintain a balance between the stimulating and inhibitory effects of sesquiterpene lactones.

2.4 Insecticidal activity

Currently, two types of termites Anacanthotermes turkestanicus Jacobs and Anacanthotermes ahngerianus Jacobs are widespread in Uzbekistan, which cause enormous damage to historical cultural monuments, buildings, structures and strategically important objects, present a special danger and a serious problem in the social and economic life of society. Although, large-scale work is underway to reduce the termite population, their distribution and the damage they cause is growing every year. Termites are social insects that can multiply quickly, endure the influence of extreme environmental factors and migrate from an unfavorable habitat to places more suitable for their habitat. Termites are able to preserve vitality and reproduce, even when part of the colony is torn off from primary reproductive individuals. Various chemicals used against termites have a short-term effect (3–5 days), and they also create problems associated with ecology and health, so the use of most of them is prohibited. In this regard, there is a need to develop new methods and means of controlling termites using poisonous food lures of intestinal prolonged action.

Recent studies have shown that cyclic sesquiterpenoids produced by plants of the Asteraceae and Apiaceae families are the most promising thermicidal preparations of intestinal prolonged action. For example, American researchers found that sesquiterpene lactone knicin with a germacrane type of skeleton isolated from Centaurea maculosa and sesquiterpene ketone vulgarone B from Artemisia douglasiana led to a high mortality rate among invasive termites. It was established that vulgarone B was lethal for termites with a quick effect. On the fourth day after administration, vulgarone B showed a 97% mortality rate. Knicin acted more slowly, and on day 15 after completion he led to 81% termite mortality. Other authors found that the simultaneous use of several terpenoids with other additives leads to increased insecticidal activity. For example, a mixture of vulgarone B and knicine in low concentrations resulted in 96–100% termite mortality on day 15 after application [16, 17].

Our phytochemical studies established that the plants of the flora of Uzbekistan are rich sources of terpenoids. To date, as a result of joint research in Tashkent State agrarian University, Institute of the Chemistry of Plant Substances AS. Ruz, Institute of Zoology AS. Ruz, a number of effective antitermitic sesquiterpenoids of intestinal prolonged action from the domestic flora, such as knicin, kumambrin A, artemisinin, arteannuin B (Figure 3), which, when used individually, have been identified 96–100% termite death for 6–10 days of use (Table 6) [18, 19].

Figure 3.

Structural formulae of isolated Аntitermitic sesquiterpene lactones.

Concentration	Number of termits	Observation day
		1		2		3		4		5		6		7		8		9		10
		п	ж	п	ж	п	ж	п	ж	п	ж	п	ж	п	ж	п	ж	п	ж	п	ж
1. 0.001	20		20		20	1	19	—	19	2	17	—	17	2	15	5	10	7	3	3	0
2. 0.003	20		20	4	16	4	12	4	8	1	7	7	0								0
3. 0.001	20		20		20	—	20	—	20	5	15	—	15	7	8	7	1	1	0		0
4. 0.003	20		20	4	16	6	10	—	10	7	3	2	1	1	0						0
5. 0.001	20	12	8	—	8	—	8	3	5	—	5	3	2	—	2	2	0		0		0
6. 0.003	20	3	17	1	16	2	14	5	9	1	8	—	8	3	5	5	0		0		0
Control	20		20		20		20		20	1	19	—	19	—	19	3	16	1	15	0	15

Table 6.

Trial results of antitermite activity of sesquiterpene lactones artemisinin, knicin and kumambrin A.

Note: П—dead termites; Ж—living termites; 1, 2—artemisinin; 3, 4—knicin; 5, 6—kumambrin A.

Using the HPLC method, a stage-by-stage control of the production of the technological process for obtaining thermicidally active sesquiterpene lactones salonitenolid and knicin from Centaurea squarroza and Jurinea maxima, kumambrin A from Handelia trichophylla, artemisinin and arteannuin B from Artemisia annua was developed.

3. Conclusion

A phytochemical study of sesquiterpene lactones of some plants of the Asteraceae family, followed by a study of their biological activity, has established a pronounced growth activity of sesquiterpene lactones isolated by us from plants of the genus Artemisia, which improves the quality and increases the yield of rice by 12–14 c/ha and increases the productivity of mulberry cocoons. On the basis of the total lactones of Artemisia absinthium, which has mutagenic activity, two new varieties of cotton with economically valuable traits have been created. Created anti-viral, anti-nosema and anti-termite agents based on the amount of lactones isolated from plants Artemisia leucodes, A. annua, A. tenuisecta, Centaurea squarroza, Acroptilon repens and Handelia trichophylla showed high antiviral activity to combat nuclear polyhedrosis and nosematosis of the silkworm, as well as brightly pronounced insecticidal activity, which destroys termites by 96–100%.

Using the HPLC method, a stage-by-stage control of the technological process for obtaining and determining the quantitative and qualitative composition of BAS in plant raw materials and extracts has been developed. Patents for the invention have been obtained for the growth and insecticidal activity of individual lactones.

Thus, the study of BAS flora of Uzbekistan is very relevant and promising, which will lead to the creation of highly effective environmentally friendly products for medicine and agriculture, the conservation of biodiversity and the rational use of local plant materials.