Triterpenoids from Gymnema sylvestre and Their Pharmacological Activities

Abstract

Because plants are estimated to produce over 200,000 metabolites, research into new natural substances that can be used in the pharmaceutical, agrochemical and agro-industrial production of drugs, biopesticides and food additives has grown in recent years. The global market for plant-derived drugs over the last decade has been estimated to be approximately 30.69 billion USD. A relevant specific example of a plant that is very interesting for its numerous pharmacological properties, which include antidiabetic, anticarcinogenic, and neuroprotective effects is Gymnema sylvestre, used as a medicinal plant in Asia for thousands of years. Its properties are attributed to triterpenoidic saponins. In light of the considerable interest generated in the chemistry and pharmacological properties of G. sylvestre triterpenes and their analogues, we have undertaken this review in an effort to summarise the available literature on these promising bioactive natural products. The review will detail studies on the isolation, chemistry and bioactivity of the triterpenoids, which are presented in the tables. In particular the triterpenoids oxidised at C-23; their isolation, distribution in different parts of the plant, and their NMR spectral data; their names and physico-chemical characterisation; and the biological properties associated with these compounds, with a focus on their potential chemotherapeutic applications.

A novel Gymnema sylvestre extract protects pancreatic beta‐cells from cytokine‐induced apoptosis

“…Characterization of alcoholic extracts of GS yielded a group of low molecular weight compounds called saponin glycosides (Ahamad, Amin, & Mir, ; Ali Ahmed, Rao, & Rao, ; Dateo & Long, ; Fabio, Romanucci, De Marco, & Zarrelli, ; H. M. Liu, Kiuchi, & Tsuda, ; Murakami et al, ; Rao & Sinsheimer, ; E. R. Shanmugasundaram, Venkatasubrahmanyam, Vijendran, & Shanmugasundaram, ; Sinsheimer & McIlhenny, ; Sinsheimer & Rao, ; Sinsheimer, Rao, & McIlhenny, ; Zhang et al, ; Zhu et al, ). Although several studies have attributed the antidiabetic effect of GS to these chemicals (Baskaran, Kizar Ahamath, Radha Shanmugasundaram, & Shanmugasundaram, ; Di Fabio, Romanucci, Zarrelli, Giordano, & Zarrelli, ; Fabio et al, ; Fushiki, Kojima, Imoto, Inoue, & Sugimoto, ; Kumar et al, ; Murakami et al, ; Reddy, Latha, Vijaya, & Rao, ; Sathya, Kokilavani, & Gurusamy, ; Sugihara et al, ), we suggest that the active constituents in OSA® extract are different. Thus, OSA® was prepared by a molecular weight cutoff isolation procedure that allows exclusion of the majority of low molecular weight saponin constituents and retention of high molecular weight (at least 3 kDa) compounds.…”

Assessment of the Acute and Subchronic Toxicity and Mutagenicity of Sideritis scardica Griseb. Extracts

“…These data may be used during authorization or registration procedures as well-established use (WEU) or traditionally used (THMP) herbal medicinal products in the European Community, and might provide valuable information particularly in respect to therapeutic use, tolerability, and toxicity [13,14,15,16]. Attention should be paid to biological effects that are difficult to detect clinically.…”

Triterpenoids

“…14 As many of the active compounds are saponins there has been an interest in their synthesis 15 and biosynthesis. 16 Reviews have also appeared covering triterpenoids found in Astragalus species, 17 Gymnema sylvestre, 18 Panax species, 19,20 Sapindus species 21 and Siraitia grosvenorii 22 and plants of the Schisandraceae. [23][24][25] Triterpenoid biosynthesis in plants 26 and the mechanisms of oxidosqualene cyclases 27 have also been covered.…”