Spices Are Also Medicine: Some Studies on Antioxidant and Antibacterial Activities of Spice Plants in Vietnam

Abstract

Spices are commonly used in the daily meals of Vietnamese families. They not only bring a specific flavor to the dishes but are also drugs that help naturally increase disease resistance. Spices are also used in folk remedies to cure or prevent certain diseases. When the world faces the quick change of pathogenic microorganisms, antibiotic-resistant bacteria regularly appear, then searching for more natural sources of medicine becomes necessary. Many studies have been conducted to screen bioactive substances from the rich and diverse plant sources of Vietnam. Extracts from spices and several spice mixtures were evaluated for their antioxidant and antimicrobial activities, indicating their potential as medicine. In this chapter, some research on the antioxidant and antibacterial activities of spice plants in Vietnam and some traditional ways to use spices as medicine will be presented.

1. Introduction

Plant-based spices are added to dishes to give them a certain smell and taste. In the cuisine arts of countries around the world, the combination of spices helps to create the characteristics of each dish as well as the characteristics of each country’s cuisine. Although spices and herbs are often classified as spices which are the dry parts of the plant and herbs as the leaves [1], Vietnamese people often use both fresh and dry types as spices.

Vietnamese food culture is diverse with many delicious dishes. The spices are associated with the dish’s main ingredients such as galangal with dog meat, lime leaves with chicken, ginger with fish, lemongrass with shrimp. The spices are also associated with the cooking methods, for example, garlic with stir-fried dishes, lime or kumquat with salads, ginger or lemongrass with boiled dishes, five-spice powder (mixture of cinnamon, fennel seeds, star anise, Sichuan peppercorn, and cloves) with fried or grinned dishes. Spices are essential ingredients to create the characteristics of Vietnamese dishes, and they are commonly used in the daily life of Vietnamese families. Spices are also used as natural drugs in folk remedies to cure or prevent certain diseases.

Many studies in the world have been conducted with spices [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. The antibacterial activity of six common spices including clove (Syzygium aromaticum L.), black pepper (Piper nigrum L.), turmeric (Curcuma longa Linn), ajowan (Trachyspermum ammi L.), coriander (Coriandrum sativum L.), and cinnamon (Cinnamomum zeylanicum Bl.) against 10 bacteria strains was studied. The results indicated that the main active compounds in those spices were probably in their essential oils and cinnamon followed by clove had the highest antibacterial capacity [2]. An elaborate review that consulted 241 pieces of literature on antibacterial and antifungal characteristics in spices was also performed. Thereby that summarized the evaluating studies about the antibacterial ability of spices such as cinnamon, black pepper, coriander, clove (Eugenia caryophyllata), oregano (Origanum vulgare), thyme (Thymus vulgaris), cumin (Cuminum cyminum), rosemary (Rosmarinus officinalis), garlic (Allium sativum), ginger (Zingiber officinale), basil (Ocimum basilicum), fennel (Foeniculum vulgare), and galangal (Alpinia galangal). Many other spices were also determined by anti-microorganisms such as yarrow, cardamon, dill, calamint, croton, poejo, hyssop, lavender, lichen, nutmeg, basil, aniseed, savory [3].

The diversity of plants that can be used as spices is enormous. Beside popular spices that are mentioned previously, there are many others such as rosy garlic, wild garlic, oriental mustard, black cumin, chili pepper, bitter orange, common croton, horned poppy, common fennel, bay laurel, fever tea, mountain pepper, lemon balm, peppermint, myrtle, lesser cat-mint, black cumin, holy basil or tulsi, clove basil, common olive, sweet marjoram, African long pepper or wild pepper, Sicilian sumac or elm-leaved sumac, garden sage, campion, summer savory, black thyme or Mediterranean thyme [3]. There are some problems in identifying them. Many spices are commonly named after regions; however, it is not clear the region of plant growth or the place where the spices are used. For example, Ethiopian cardamom, Persian shallot, Indonesian cinnamon, Persian cumin, Mexican oregano, Spartan oregano, English mint, Macassar nutmeg, Dutch myrtle, American basil, African basil, Java tea, Syrian rue, Jerusalem sage, Mediterranean thyme, Sicilian sumac, Jamaica pepper, African long pepper, Ashanti pepper or Benin pepper. There are many synonymous scientific names for the same spices; for example, Trachyspermum ammi and Carum capticum (ajwain or ajowan), Eugenia caryophyllata and Syzygium aromaticum (clove). Some relative species belong to the same genus but are called with different common names as different spices, for example, small peppermint (Thymus piperella) and creeping thyme (Thymus serpyllum). Even, one certain plant species is called as different spices, for example, conehead thyme or Persian-hyssop, or Spanish oregano all are Thymus capitata (or Thymus capitatus). Some plants are used without any common name such as Thymus eigii.

Spices are known to have many antioxidants [4, 5, 6, 11]. They are mainly bioactive secondary metabolites of plants, which consist of terpenes, phenolic compounds, and nitrogen-containing compounds. The mechanisms such as blocking free radicals, acting as oxygen scavengers, and chelating metal ions capable of catalyzing oxidation are the main actions of antioxidants [4]. The antioxidant capacity of spices has been assessed mainly because of their essential oils, so fresh herbs are often found to have high antioxidant capacity. Therefore, the extraction solvent affects the antioxidant capacity of spices in the studies [4, 6]. Daily, spices are often used raw, in hot water, or soaking in wine for a period (then using wine). Water and alcohol solvents become important solvents when evaluating the effectiveness of spices as natural antioxidants. Milda E. Embuscado reviewed the antioxidant activity of hot water extracts of spices and showed four spices including clove, thyme, rosemary, and savory that had DPPH radical scavenging activities higher than 50% [4]. Usually, spices are used in combination rather than individually, so studies on the differences in bioactivities of individual spices and the combination of spices and mixtures of spices with some other compounds are also of interest [5].

In Vietnam, studies on the antibacterial and antioxidant activities of spices have also been conducted on a wide range of species, varieties, cultured areas, methods of extracting bioactive compounds, etc. In this chapter, several studies are mentioned as examples of the priority research directions on spices in Vietnam. More importantly, some traditional therapies of using spices in disease prevention and treatment are presented for readers to understand more about the role of spices in Vietnam.

2. Some research on the antioxidant and antibacterial activities of spices in Vietnam

In Vietnam, through traditional uses, there have been some summaries on the antibacterial and antioxidant capacities of daily used spices [12, 13]. Many spices are also mentioned in the list of medicinal plants in Vietnam [13, 14]. Since 1961, the direct extracts from garlic (Allium sativum L.) and fragrant garlic (Allium odorum L.) in Vietnam have been found that have antibacterial activity against seven bacteria strains (according to [13]). Inhibition zone diameters of the fresh garlic extract were greater from 1.5 to 2.5 times than fragrant garlic extract, and they lost their activities if used in the form of decoction. Vietnamese balm (Elsholtzia ciliata) is known as effective in treating many diseases, including flu, cold, allergies, bleeding nose, and ban on speech (traditional ion therapy also mentions leprosy). A study on Vietnamese balm showed that its essential oil contains many active substances and the most abundant was verbenol. Vietnamese balm essential oil inhibited the growth of E. coli as well as Salmonella [15].

Searching for new effective and safe cures, and new therapeutic modalities in disease prevention and treatment has always been of great interest to researchers in the world. In recent years, studies on bioactivities and bioactivity compounds from plants have also been widely conducted in Vietnam. And beside medicinal plants, spices are a group of plants that are of great interest. In studies on antibacterial activity, spices were studied and compared with medicinal plants [16]. According to the research on in vitro antibacterial activity of 18 eligible herbs and 21 medicinal plants against six strains of Burkholderia pseudomallei (causative agent of melioidosis), and seven other enteric bacteria, garlic, and fragrant garlic juices showed a broad spectrum of antimicrobial activity but lost its activity when was treated with high temperature [16]. The juice, the aqueous extract, and the alcohol extract of different plant parts were also tested and compared quite often because of the traditional ways to use the spices. The bioactivity compounds of plants may vary in content in different parts of plants grown in different regions [17, 18]. Lemongrass (Cymbopogon citratus) plants from three provinces: Hoa Binh, Ha Nam, and Nam Dinh were separately extracted essential oil in stems and leaves [18]. The results showed that lemongrass essential oil had antibacterial activities against Enterococcus faecalis, Shigella flexneri, Escherichia coli, Streptococcus pneumoniae, Staphylococcus aureus, and Klebsiella pneumoniae but not Salmonella typhi. Lemongrass oil extracts from stems inhibited the growth of bacteria better than extracts from leaves. Essential oil from Hoa Binh province lemongrass has both better antioxidant and antibacterial properties than plants from other provinces. Especially, the essential oil from both leaves and stems of plants collected from Nam Dinh province did not have anti-Streptococcus pneumoniae activity, while those collected from the other two provinces did [18]. There are some fruits that fruit juice is commonly used to drink as lime and kumquat are considered spices in Vietnam. Kumquat (Citrus japonica Thumb.) is one of the decoration plants in the traditional Tet holiday in Vietnam as the symbol of prosperity and affluence. In folk remedies, kumquat can be used as an ingredient for cough treatment and digestive support, and is good for the liver and spleen. Biological active substances contain in lime (Citrus aurantifolia) juice can reduce scurvy, a vitamin C deficiency symptom that leads to gingivitis, spontaneous bleeding, and weakness. Lime is used to treat fever and cough, and indigestion in tradition. Recently, studies have shown that lime concentrate has antibacterial and antioxidant properties and has a protective function against liver cell damage due to the harmful effects of alcohol (following the review in [19]). The combination of lemongrass stalks and the peels of lime, ginger tubers, and kumquat peels were tested for antioxidant and antibacterial activities and comparison of their activities with the activities of some medical plants was made [20]. The extract of ginger and kumquat mixture at the concentration of 0.1 mg/ml presented the highest free radical scavenging activity in the study. The activity even was 1.4 to 1.6 times greater than Pluchea indica and Stephania glabra (two medicinal plants). Extract of ginger and kumquat mixture was also effective in inhibition against Bacillus cereus, Staphylococcus aureus, and Vibrio parahaemolyticus through the agar well diffusion assay greater than Drynaria fortunei and P. indica; however, less than the ability of the extract of S. glabra [20]. The antibacterial ability of spices in addition to drug development applications for humans has also been studied with pathogenic microorganisms on animals and plants applied in the fields of agriculture, cultivation, and animal husbandry [21, 22].

The comparison between the antioxidant abilities of close species or different varieties was done in Vietnam due to the enormous diversity of plants. Antiseptic, deworming, and detoxification of vines in family of Paederia attract the attention of researchers. A study that assessed and compared the antioxidant activity of sewer vines (P. lanuginose Wall.) and stink vines (P. foetida L.) was done [23]. Vine leaves are found to have high levels of polyphenols and vitamin C, which mainly contribute to the antioxidant activity of their extracts. The drying process may cause the decrease in bioactivity [23]. Ethanol extracts of three spices: turmeric (Curcuma longa), green turmeric (C. yunnanensis), lesser alpinia (Alpinia conchigera), and five other plants were tested antioxidant and antifungal activities in a study [24]. The total polyphenol content in C. longa extract was about 4.5 times higher than in C. yunnanensis (44,87 ± 0,14 compared to 10,07 ± 0,18 mg GAE/g extract), while the flavonoid content of green turmeric was light higher (144,98 and 110,75 ± 6,38 mg QE/g extract). A. conchigera was observed possessing highest flavonoid content in ethanol extract, 2.5 times higher than turmeric. Research has also shown that turmeric (yellow turmeric) has a higher antioxidant capacity than green turmeric [24]. It is understandable why yellow turmeric is used more commonly than green turmeric.

Other research directions with spices (as well as with bioactive plants) are the study of methods to evaluate extract composition, protocols to extract, and purify of potential bioactive compounds beside evaluating bioactive activities [25, 26]. The development of nanotechnology with the potential of targeted drug delivery is also a new research direction using extracts from spices. Turmeric became a potential object of nano-research due to its well-known active ingredient curcumin [27, 28, 29]. Then, other spices have also been noticed. Some bioactive compounds found in spices as rutin, allicin, gallic acid, quercetin, … are the potential materials for nanoparticle formation. A study was done to synthesize silver nanoparticles using shallot (Allium ascalonicum L.) in Nong Lam University, Ho Chi Minh City. Pleasant Himalayan mint (Elsholtizia blanda) and Padang cassia (Cinnnamomum burmanni) were in the list of 19 plants screened for synthesis silver nanoparticles in the University of Medicine and Pharmacy in Hanoi [14]. The bioactivity of nano-spices was also tested. Nano-silver particles synthesized using ginger extract as a reducing agent have shown antibacterial activity on both Gram (−) and Gram (+) strains presentative by E. coli and S. aureus [30].

3. Some traditional ways to use spices as medicine in Vietnam

In Vietnam traditional methods to prevent flu raw garlic, ginger, galangal, lemongrass, as well as scallion are regularly used. In the countryside, many families have a bottle of alcohol at home with soaked garlic inside, to cure the flu, fever, back pain, stomach pain, difficult digestion, flatulence, running nose, stuffy nose or even sinusitis, and hypertension. Parts of plants such as leaves, bud, flower, fruit, seeds, root, rhizome, stem or even bark are used as spices, as well as medicine. There are many ways to make spices into medicine. Eating raw spices is easy and common and can be daily used but to treat certain diseases the dose needs to be increased. Fresh juice of spices that are extracted by grinding or crushing fresh material and extract solution. The same way to make fresh juice but in addition of an amount of water can be done with fresh and dried spices after filtering aqueous extracts are obtained. Spice of wine is obtained by soaked materials in water or in wine (alcohol) in a period. Decoction means slowly cooking/boiling the plant parts in water. With wounds, skin diseases or diseases of muscles, bones and joints, spices can be crushed or chopped and applied to the painful area. Sometime spices are pulverized into fine powders, and sometimes spices tea can be made by being kept in hot water for a while. Essential oils are quite often extracted from both fresh and dried spices depending on the species. The ways to use individual spices were summarized (Table 1).

Scientific name	Vietnamese name/common name	Treatment diseases	Ways to use
Allium fistulosum L.	Hành/ spring onion, scallion	Cough, expectorant, diuretic, reduce malaria, edema	Eat raw; Drink scallion juice
		Blister	Apply crushed leaves to the pain
		Pustules	Scallion essential oil
		Rhinitis, stuffy nose	Drop scallion juice into the nostrils
		Threatened miscarriage	Decoction
Allium odorum L. or A. tuberosum Roxb.	Hẹ/ fragrant garlic	Cough, diarrhea, flu, flatulence	Eat raw; Drink fresh juice
		Nocturnal emission	Aqueous extracts of leaves or fruits
Allium sativum L.	Tỏi/garlic	Flu, typhoid, cholera, diphtheria	Eat raw or drink garlic juice
		Dysentery	Garlic crushed in water, filter to extract garlic water to drink and apply to the pain
		Flu, sinusitis, bronchitis hypertension	Garlic wine
		Snake bite	Apply crushed garlic to the pain
Alpinia officinarum Hance	Riềng/ galangal	Stomachache, diarrhea, flatulence, indigestion, cold, fever, vomiting	Decoction; Drink fresh juice; Galangal wine
		Toothache	Chew raw galangal
Amomum aromaticum Roxb.	Thảo quả/cardamon	Malaria, stomachache, vomiting, phlegm, poor spleen function	Use fruit powder
		Halitosis	Crush fruits, keep in mouth
Amomum longiligulare and A. villosum Lour., Acanthospermum xanthioides Wall.	Sa nhân/ amomum	Toothache	Keep seeds in mouth
		Stomachache, flatulence, indigestion, cholera, dysentery	Eat seeds
Anethum graveolens L. or Peucedanum graveolens	Thìa là/dill	Cold stomach, flatulence, vomiting, urinary retention	decoction of dried plant
		Mother’s milk insufficiency	Essential oil extract from fruits
Cinnamomum loureirii Nees. and Cinnamomum cassia, C. zeylanicum	Quế/cinnamon	Arm and leg spasms/cramps, Back and knee numbness, abdominal pain, menstrual blockage/ amenorrhea, urinary retention	Cinnamon powder; Cinnamon tea
Coleus aromaticus Benth or C. crassifolius Benth	Húng chanh/ soup-mint	Flu, cough, asthma,	Eat raw; Drink fresh juice
		Insect stings	Apply crushed leaves to the pain
Coriandrum sativum L.	Mùi/coriander	Reduce complications of measles	Apply crushed coriander fruits mix with coriander wine to the body
		Cold, cough, fever, headache	Aqueous coriander
		Mother’s milk insufficiency	Boil coriander fruits in water, drink the water twice a day
Curcuma longa L. or C. domestica Lour. And C. xanthorrhiza	Nghệ/turmeric	Wound, get a burn	Apply fresh rhizome extraction to the pain
		Stomach ulcers	Eat turmeric powder/turmeric powder mix with honey
		Hemoptysis, nosebleed	Orally use turmeric powder with water
		Skin swelling, arthritis	Turmeric wine
		Infected wound, uterine ulcer, cervicitis	Turmeric oil
Cymbopogon nardus Rendl and Cymbopogon citratus	Sả/ citronella grass and lemon grass	Urinary retention, fever	Drink fresh juice from stack or decoction; Lemongrass essential oil
Elsholtzia cristata Willd or E. ciliata (Thunb.) Hyl.	Kinh giới/ Vietnamese balm or crested late summer mint	Fever, headache, nosebleeds, bloody stools, bloody urine	Decoction (dried whole plant)
		Loss speech	Make tea with dried flower powder
		Allergies
Enhydra fluctuans Lour. or Cryphiospermum repens, Hingtsha repens, Tetraotis paludosa	Ngô�/helencha, water cress, buffalo spinach	Abdominal distension, hemorrhage, hemoptysis	Decoction (shoots)
		Inflammation	Apply crushed shoots
Houttuynia cordata Thumb.	Diếp cá/ fish mint	Hemorrhoids, pimples	Eat raw; Drink fresh juice; Apply crushed leaves to the pain
		Headache	Apply crushed leaves on forehead
		Irregular menstruation, urinary retention	Decoction (dried whole plant)
Illicium verum Hook.f.	Hồi/star anise	Indigestion	Decoction (fruits)
		Pain, numbness	Apply star anise wine to the pain
Mentha arvensis L.	Cây bạc hà/ corn mint	Flu, cough, stuffy nose,	Eat raw; Drink fresh juice
		Headache	Massage forehead with mint oil
		Rash	Apply crushed leaves
Ocimum basilicum L.	Húng quế/basil	Sore throat, chicken cough, stomachache, toothache	Eat raw leaves; Use essential oil
		Constipation, urinary retention,	Aqueous extract
Paederia tomentosa L. or P. foetida	Mơ tam thê�/ skunkvine	Dysentery	Eat fried egg mixed with small cut leaves
		Kidney stones, urinary retention	Decoction leaves
		Rheumatism and numbness	Drink juice extracted from leaves and massage with residue
Perilla frutescens	Tía tô/ Vietnamese perilla	Cough, digestive stimulant, pain relief, detoxification	Eat raw or dried leaves
		Asthma, rheumatism	Decoction dried fruits
Petroselinum sativum Hoff. or Carum petroselium	Mùi tây/Persil	Urinary retention, irregular menstruation	Decoction fruits
		Inflammation	Apply crushed leaves
Piper lolot C. De	Lá lốt/lolot	Bone pain, rheumatism,	Decoction dried leaves
		Diarrhea	Decoction dried leaves
		Sweaty feet/hands	Foot/hand bath with warm water of slowly cook dried leaves
Piper nigrum L.	Tiêu/black pepper	Stomachache, cold	Pepper wine
		Indigestion	Pepper/ pepper powder
Polygonum odoratum Lour.	Răm/ Vietnamese coriander	Reduce libido, vomiting, urinary retention	Eat raw
		Ringworm, impetigo	Crush leaves, add wine and apply to the pain
		Snake bite	Crush leaves, extract juice to drink, and apply residue to the pain
Syzygium aromaticum L. or Eugenia caryophyllata	Đinh hương/clove	Diarrhea, vomiting, stomachache, indigestion	Use dried clove buds
		Toothache	Clove essential oil
Zingiber officinalle Rose	Gừng/ginger	Vomiting	Take a slice of ginger
		Sore throat, cough	Drink hot water/tea adding ginger; Take a slice of candied ginger
		Cold, flu, headache	Massage body with ginger wine
		Cholera, dysentery	Grind dried ginger, orally use with rice water or porridge

Table 1.

Vietnamese traditional ways to use spices to treat common diseases [12, 13].

Spices are also used in combination with each other and with some other herbs or plants to treat several diseases in daily life (Table 2).

Combination	Disease treatment	Way to use
Dried ginger, galangal	Malaria, fever, loss of appetite	Mix grind powders with pig gallbladder fluid to make pills, orally use the pills
Ginger, cardamon, chebulic myrobalan - kha tử (Terminalia chebula Retz.)	Malaria, a cold, dehydration, loss of appetite	Decoction
Dried ginger, licorice—cam thảo (Glycyrrhiza glabra)	Headache, cold stomach, vomiting, phlegm	Decoction
Ginger, rhizome of Bengal arum—bán hạ chế (Typhonium trilobatum (L.) Schott.)	Asthma, vomiting	Decoction
Black pepper, Bengal arum, ginger	Diarrhea and vomiting	Equal mixture of grinded pepper and Bengal arum, orally use with ginger water
Dried fish mint, common jujube—táo tàu (Ziziphus jujuba) fruit	Middle ear swelling, milk duct swelling	Decoction
Galangal, lemon grass, pomelo—bưởi (Citrus maxima (Burm.) Merr.)	Flu, cold	Boil leaves in water, take a bath
Vietnamese perilla, lemon grass, bamboo—tre (Bambusa arundinacea (Retz.) Willd.), pomelo	Flu, cold	Boil leaves in water, take a bath
Vietnamese balm, Vietnamese perilla, tulsi—hương nhu (Ocimum sanctum L.)	Vomiting	Eat raw mixture of leaves
Vietnamese balm, ginger	Arthritis	Apply crushed leaves adding with crushed ginger to the pain

Table 2.

Some of the spices combination and spices combine with other plants are used in disease treatment [13].

4. Conclusion

Plant-based spices are used in daily life to help us naturally resist some common diseases. We can still rely on spices to be cured from runny nose, headache, cold, and flu without knowing it. It is thanks to the antibacterial and antioxidant properties of spices that they can resist diseases. Spices also have antifungal activity, the ability to inhibit cancer cell development, increase resistance, immune system support, supplement nutrition, etc. Spices have been and will be a potential source for research and development of new drugs. Indeed, spices have long been present in Vietnamese remedies to treat several diseases as summarized in this chapter. Research on spices will still be carried out more deeply and widely to exploit this marvelous source of medicine.