Important Medicinal Plants in Ethiopia: A Review in Years 2015 – 2020

Many studies on medicinal plants have been taking place in different parts of Ethiopia and the people use them for the preparation of traditional herbal medicine. The purpose of the current study is to review the assessment of the medicinal plants used in Ethiopia, to compile the components used, the method of preparation, the medical uses, and the compilation of the number of medicinal plants in 2015 – 2020. This review paper took place in the years 2015 to 2020 from the published papers. Various databases, such as Science Direct, PubMed, and Google Scholar, have been searched. The data were analyzed using frequency, percentages, charts, and numbers using the Microsoft Excel spreadsheet 2010. In Ethiopia, a total of 4,007 medicinal plants were identified from different areas by different authors in the years 2015 – 2020. But, from this total number of identified medicinal plants, there was a similarity between types of plant species. Therefore, this total result has present similarities in plant species and types found in different areas. In 2015, a total of 1,062 medicinal plants were identified from different areas by different authors. Similarly, 315, 613, 944, 341, 732 medicinal plants were identified by different authors in different study areas in the years 2016, 2017, 2018, 2019, and 2020 respectively. The years 2015 and 2018 were the years many plants of medicinal value were documented. The growth forms of medicinal plants were analyzed from 2015 to 2020 in the different study areas with different authors but with the same year and valued for each year and put the average one. To calculate the 2015 growth form of medicinal plants for example to calculate herbs, add all herbs identified by different authors in the same year, and take the average one. This method applied to all growth forms of medicinal plants each year. In all years (2015 – 2020) the dominant growth forms were herbs. The highest average of growth form was herb in the year 2020 which is 44.2%. In all years the least growth form was a climber. In all growth forms, the parts used for medicine were identified. Add each medicinal plant ’ s parts in the same year and then take the average for all years. In 2020 year, the traditional healers mostly used the preparation of remedy in the year 2015 – 2020. Also, powdering, boiling, chewing, concoction, grinding, direct and immediate, chopping, squeezing, decoc-tion, boiling/unprocessed use, liquid form, Homogenizing in water, heating, cooking, smoking, and fumigation are common methods of preparation of remedy. In general, this review highlights the situation of Ethiopian traditional medicinal plants associated with their knowledge from years to years. In addition, this review paper plays an important role in the extraction of potential medicinal plants to discover new drugs through detailed researches in the future.


Introduction
Ethiopia is the sixth major country in tropical Africa in terms of the diversity of flora [1]. The country is endowed with rich flora, having more than 6,500 species of vascular plants out of which an estimated 12% are endemic and many plant species are used as medicinal plants [2,3]. In Ethiopia, 80% of people depend on traditional medicine for their health care, and more than 95% of traditional medicinal preparations are made from plant origin [4]. Ethiopia is also a home for many languages, cultures and beliefs that have in turn contributed to the high diversity of traditional knowledge and practice of the people, which, among others include the use of medicinal plants [5,6]. Ethiopian traditional medicines are greatly complex because the country harbors much cultures and endogenous knowledge [7].
Medicinal plants are plants that are used to treat diseases of humans and animals [8]. Traditional healers practice on these plants using their indigenous knowledge and hence, they are called traditional medicines. Primitive peoples in all ages have had some knowledge of medicinal plants derived as the result of trial and error [9]. Medicinal plants were traditionally used for health care and serve as the bases for the emergence of modern medicine. About 6,000 medicinal plants are believed to be used in traditional medicine globally [10][11][12]. Most of the medicinal plants are directly used from the wild and some from home gardens. However, home gardens played important role in cultivating and retaining medicinal plants beyond other useful plants [13]. Ethnobotanical knowledge as part of living cultural knowledge and practice between communities and the environment is essential for biodiversity conservation [14][15][16]. Most traditional medical treatments put into performing in Ethiopia rely on an amplification of disease that draw on both the "mystical" and "natural" base of medical circumstance and put together use of a holistic approach to management [17]. The usage of herbal medicine in Ethiopian patients in the treatment of diseases like cancer, liver, neurological and hepatic diseases were reported by some authors [18,19]. In general plants are very important in Ethiopia to treat various ailments.
The present review was conducted to gather information about the plants used by people of Ethiopia in traditional medicine in the years 2015 to 2020, such as to highlight the description of medicinal plants including local name, the parts used, the preparation methods, traditional uses, and to compile the number of medicinal plants in each year till 2015 to 2020. This is believed to show the importance of traditional knowledge on treating ailments and elucidate the degree of development of this knowledge to marketable business.   have been searched. The data were analyzed using frequency, percentages, charts, and numbers using the Microsoft Excel spreadsheet 2010.

Medicinal plants in Ethiopia
In Ethiopia many medicinal plants are useful for treatment of different health problems. As indicated in Table 1

Identified medicinal plants in Ethiopian in the years 2015-2020
The

Growth forms (habits) of medicinal plants
The growth forms (habits) of medicinal plants was analyzed from 2015 to 2020 in different study area with different authors but with the same year and valued for each year and put the average one. To calculate the 2015 growth form of medicinal plants for example to calculate herbs, add all herbs identified by different authors in the same year and taken the average one. This method applied for all growth form of medicinal plants to each year (Figure 2). In all years (2015-2020) the dominant growth forms were herbs. The highest average of growth form was herb in year 2020 which is 44.2% (Figure 2). In all years the least growth form was climber (Figure 2).

Parts of medicinal plants
In all growth forms, the parts used for medicine were identified. Add each medicinal plants parts in the same year and then taken the average for all years (Figure 3). In 2020 year the traditional healers mostly used leaves (56.3%) for the  preparation of remedy. In general, in all year leaves was the dominant for the preparation of remedy (Figure 3).

Route of administrations
Oral and dermal ways of route of administration were the most important in medicinal plants to treat directly different ailments. The route of administration was varying in percentage from year to year and also, place to place according to the potential of traditional healers and type of diseases. But, in different study areas and years showed that oral administration was dominant one (Figure 4). In 2019, most of the prepared remedy was taken orally.

Methods of preparation of medicinal plants
Crushing was the most important and more cited in the preparation of remedy in the year 2015-2020 ( Table 2). Also, powdering, boiling, chewing, concoction, grinding, direct and immediate, chopping, squeezing, decoction, boiling/ unprocessed use, liquid form, Homogenizing in water, heating, cooking, smoking and fumigation are almost common for many traditional healers were shared methods to preparation of remedy.

Conclusion
All the medicinal plants reported in the current review work have been used in traditional medicine for the treatment of different human ailments in Ethiopia. But, the studied plants in the present review need further investigation for detailed extraction of natural products, pharmacological and biological activities as well as a safety control. Therefore, today's review is a gateway for a new researcher to