Phytochemistry and Diverse Pharmacology of Genus Mimosa: A Review

The genus Mimosa belongs to the Fabaceae family and comprises almost 400 species of herbs, shrubs and ornamental trees. The genus Mimosa is found all over the tropics and subtropics of Asia, Africa, South America, North America and Australia. Traditionally, this genus has been popular for the treatment of jaundice, diarrhea, fever, toothache, wound healing, asthma, leprosy, vaginal and urinary complaints, skin diseases, piles, gastrointestinal disorders, small pox, hepatitis, tumor, HIV, ulcers and ringworm. The review covered literature available from 1959 to 2020 collected from books, scientific journals and electronic searches, such as Science Direct, Web of Science and Google scholar. Various keywords, such as Mimosa, secondary metabolites, medicines, phytochemicals and pharmacological values, were used for the data search. The Mimosa species are acknowledged to be an essential source of secondary metabolites with a wide-ranging biological functions, and up until now, 145 compounds have been isolated from this genus. Pharmacological studies showed that isolated compounds possess significant potential, such as antiprotozoal, antimicrobial, antiviral, antioxidant, and antiproliferative as well as cytotoxic activities. Alkaloids, chalcones, flavonoids, indoles, terpenes, terpenoids, saponins, steroids, amino acids, glycosides, flavanols, phenols, lignoids, polysaccharides, lignins, salts and fatty esters have been isolated from this genus. This review focused on the medicinal aspects of the Mimosa species and may provide a comprehensive understanding of the prospective of this genus as a foundation of medicine, supplement and nourishment. The plants of this genus could be a potential source of medicines in the near future.


Introduction
The Mimosa genus is a member of the legumes family Fabaceae (subfamily: mimosoideae) and consists of about 400 species of shrubs and herbs [1]. Almost  Phytochemicals, such as alkaloids, flavonoids, saponins and triterpenes, were present, while sterols and tannins were found to be absent [84]. Ahuchaogu et al. screened the phytochemicals of the EtOH extract of the whole M. pudica plant. The ethanol extract consisted of alkaloids (9.05%), flavonoids (8.32%), steroids (2.49%), saponins (8.15%), phenols (1.02%), tannins (0.083%), cyanogenic glycosides (0.122%) and anthocyanins (1.913%) [85]. Durgadevi and Karthika reported the phytochemicals of the aq. extract of M. pudica leaves. A qualitative analysis indicated the presence of flavonoids, alkaloids, proteins, steroids, tannins, saponins and terpenoids, while phlobatannins, phenols and reducing sugars were found to be absent. The quantitative phytochemical investigation of saponins, flavonoids, tannins and terpenoids were 0.48 mg/mL, 0.99 mg/mL, 0.80 mg/mL, 0.39 mg/mL and 0.39 mg/mL of the aq. extract recorded, respectively [24]. Sheeba et al. screened the phytochemicals of the MeOH extracts of M. pudica leaves. The plant showed the presence of flavonoids, phenols and tannins, while alkaloids, glycosides, terpenoids, amino acids and carbohydrates were found to be absent [86]. Tunna et al. reported the presence of phytochemicals in M. pudica aerial parts. Alkaloids, saponins, flavonoids, terpenoids and coumarins were found to be present, while carotenoids and anthraquinone were found to be absent [29]. Parmar et al. measured the phytochemicals of the EtOH extract of M. pudica roots. Extracts showed the presence of tannins, alkaloids, terpenoids, flavonoids, sterols, phenolic compounds and proteins [34]. Mahadevan et al. measured the phytochemicals of aq. extract of the whole M. pudica plant. A Phytochemical analysis exhibited the existence of alkaloids, flavonoids and tannins [87]. Ramesh et al. investigated phytochemicals of various extracts (EtOH, MeOH, PE and ACE) of M. pudica leaves and roots. The results showed the presences of flavonoids, alkaloids, terpenoids, carbohydrates, saponins, amino acids, phenols, tannins, proteins and steroids, while glycosides, fats, oils, resins, reducing sugars, phytosterols and phlobatannins were found to be absent [88]. Chinnathambi and Sathasivam measured the phytochemicals of the ACE, EtOH and aq. extracts of M. pudica leaves. The investigation proved the existence of tannins, terpenoids, phlobatannins, steroids, saponins and glycoside, while flavonoids were absent [89]. Mathew et al. measured the phytochemicals of the MeOH extracts of the M. pudica plant. The results showed the existence of compounds, such as flavonoids alkaloids, saponins, terpenoids, phenols, glycosides, tannins and coumarins [26]. Nagarajan et al. determined the phytochemicals of aq. extract of M. pudica leaves and stems by using the Harborne methods [90,91]. The phytochemicals, such as saponins, alkaloids, flavonoids, tannins and phenols were present.
Nagarajan et al. determined the quantitative assessment of the mineral contents of the aq. extracts of M. pudica leaves and stems by using wet digestion extraction methods. The mineral contents, such as magnesium, phosphorus, calcium, nitrogen and potassium, were observed [91]. Lee et al. reported the presence of neoxanthin (9.86 µgg −1 FW), viola xanthin (6.57 µgg −1 FW), lutein (7.75 µgg −1 FW), lycopene (0.62 µgg −1 FW), carotene (α = 0.19, β = 0.25 vit.E −1 g), tocopherol (α = 0.25 vit.E −1 g), total Carotenoids (25.24 µgg −1 FW) and total vitamins (0.25 µgg −1 FW) in leaves of M. pudica [92]. Ittiyavirah and Pullochal determined the phytochemicals of the EtOH extract of the whole M. pudica plant. The preliminary phytochemical analysis of M. pudica revealed the existence of alkaloids, flavonoids, tannins, phenolics and steroids [93]. Ao et al. and Olusayo et al. screened the preliminary phytochemicals of the EtOH extract of M. pigra roots. The tannins, phlobatannins, flavonoids, triterpenes and saponins were found to be present, while alkaloids, anthraquinones and phenolics were found to be absent [94,95]. Rosado-Vallado et al. screened the phytochemicals of the MeOH and aq. extracts of M. pigra leaves. The result showed the existence of flavonoids, quinones, saponins, sterols and tannins [96]. Saxena et al. measured the phytochemicals of the EtOH and MeOH extracts of the whole M. hamata plant. The preliminary phytochemical analysis indicated the existence of flavonoids, alkaloids, phytosterols, glycosides, tannins, phenolic compounds, saponins and carbohydrates, while proteins and amino acids, fixed oils and fats were found to be absent [97]. Manosroi et al. reported the presence of various phytochemicals, such as flavones, glycosides, saponins alkaloids and tannins, in the aq. extract of M. invisa leaves, while anthraquinones and xanthones were found to be absent [98]. Jiménez et al. determined the total phenolic contents of the aq. extract of the whole M. albida plant by the Folin-Ciocalteu method. The plant showed a high phenolic content (323 mg GAE/g) [99]. Seraglio et al. measured the phytochemicals of M. scabrella bentham honeydew honeys. Coumarins, flavonoids, lignin-derived aldehydes and phenolic acids were found to be present [100]. Nandipati et al. reported on the flavonoids, tannins, triterpenes and carbohydrates in the MeOH extract of the M. rubicaulis stem [101]. Table 1 presents various phytochemicals present in different species of the genus Mimosa. Phytochemicals are widely known for their medicinal activities. Primary metabolites, such as proteins, lipids and amino acids, are responsible for biochemical reactions in plants, while secondary metabolites, such as saponins, flavonoids, alkaloids, tannins, phenols and glycosides, protect plants against damage and also play a role in the improvement of flavor, color and fragrance. [102]. Phytochemicals in plants are very present in leaves, roots and stems, and their percentage varies because of environmental conditions, plant genus, etc. The Mimosa genus is rich in these primary and secondary metabolites, so the plants of this genus are well known for their pharmacological potential.

Bioactive Constitutients of Genus Mimosa
The plants of genus Mimosa are well known for their rich source of bioactive metabolites. Almost 145 active metabolites have been isolated from the genus Mimosa including chalcones, alkaloids, flavonoids, indoles, terpenes, terpenoids, saponins, steroids, amino acids, glycosides, flavanols, phenols, lignoids, polysaccharides, lignins, salts and fatty esters. This part of the paper documents the isolated secondary metabolites of the genus Mimosa in the past decades and their pharmaceutical values ( Table 2). The structures of all the isolated compounds are presented in Figure 1.      [58]

Pharmacological Activities of Genus Mimosa
The potential role of the Mimosa genus in traditional medicines encouraged the further biological evaluations of organic extracts and isolated phytoconstituents for potential pharmacological applications. In this section, we summarized the pharmacological activities of genus Mimosa (Table 2).

Antioxidant Activity
The reactive oxygen species are the cause of many diseases in human beings including cardiovascular and neurological disorders [146]. There is a constant need to counteract the effect of reactive oxidative species to delay the progression on these diseases. Reactive oxygen species and free radicals are scavenged by antioxidants through the termination of a chain reaction, which otherwise can cause damage to cells [147]. Plants are a source of antioxidants and can help to lessen the diseases caused by reactive oxidative species. Natural antioxidants are more potent and less toxic, so there is a need to find more natural sources for well-being. Various species of Mimosa have been screened for antioxidant activity by the application of different assays ( Table 2)

Cytotoxic Activity
Cancer is an uncontrolled and abnormal symmetric growth of body cells [148]. Different cancers were observed in humans, such as in the liver, stomach, lung, breast, prostate, thyroid and cervix. Bioactive compounds isolated from plants are used in curing cancer because they are inexpensive, nontoxic and easily available as compared to synthetic compounds. The bioactive compounds in plants induced apoptosis in infective cancer cells and also helped to restore chemotherapy sensitivity [149]. Lin [123]. Scientists screened the cytotoxicity of the isolated (2-(2 ,6 -dimethyl-3 ,4 ,5 -alkyl or hydroxy alkyl substituted phenyl)-3-oxy-(alkyl or hydoxy alkyl) 5,7-dihydroxy-chromen-4-one) (104-107) from M. pudica using the MTT assay against human lung adenocarcinoma (A549) and the erythroleukemic cell line (K562). The compound showed significant IC 50 against A549 = 76.67 µg/mL and K562 = 287.63 µg/mL, while the positive control Doxorubicin showed an IC 50 value of 2.76 µg/mL and K562 = 4.72 µg/mL against A549 [50]. The cytotoxic potential of the amino acid L-Mimosine (108) extracted from M. pudica by the MTT assay against the daudi cell line was reported. After 72 h, the compound (108) showed an IC 50 value of 86.61 µM. Compound (108) act as powerful inhibitors of cell proliferation and showed remarkable cytotoxic activity [34,125].

Conclusions and Future Perspectives
This review summarized the isolated phytochemical and pharmacological characteristics of the Mimosa genus. Out of 400 species only 25 have been chemically studied, while compounds belonging to different chemical classes have been isolated in the Mimosa species, such as alkaloids, chalcones, flavonoids, indoles, terpenes, terpenoids, saponins, steroids, amino acids, glycosides, flavanols, phenols, lignoids, polysaccharides, lignins and fatty esters. Significant bioactivities, such as antimicrobial, cytotoxic, antioxidant, antiprotozoal, antiviral and antiproliferative, were discussed in this review. In this review, M. pudica was the most studied specie. This review also covered the qualitative and quantitative analysis of phytochemicals, such as flavonoids, steroids, saponins, alkaloids, coumarins, tannins and terpenoids, in the genus Mimosa. This review focused on the medicinal aspects of the Mimosa species and may provide a comprehensive understanding of the prospective of this genus as a foundation of medicine, supplement and nourishment. Several studies were performed to establish the pharmacological potential by identifying the bioactive secondary metabolites associated with the respective activities. Many studies have been carried out that show this genus possesses huge potential for new drug sources, but there are still gaps, which are noteworthy. Few species of this genus have been explored, so there is a need to explore all species of this genus to find their potential medicinal values for well-being. Secondly, there is a need to provide detailed mechanistic studies on the pharmacology to provide a good understanding of the application of the Mimosa species as a source of potential medicines. Thirdly, further studies are required to explore safety aspects of the diverse range of the Mimosa species, including chronic toxicity with a determination of the molecular pathways of the health-promoting features of this genus, and attempts are required to isolate more bioactive compounds of this genus.

Data Availability Statement:
The data presented in this study are available on request from the corresponding authors.