Medicinal Foodstuffs. XXI. Structures of New Cucurbitane-Type Triterpene Glycosides, Goyaglycosides-a, -b, -c, -d, -e, -f, -g, and -h, and New Oleanane-Type Triterpene Saponins, Goyasaponins I, II, and III, from the Fresh Fruit of Japanese Momordica charantia L.

Abstract

The Cucurbitaceae plant Momordica (M.) charantia L. (Japanese name "Tsurureishi") is cultivated as a vegetable in Asian countries. In Chinese, Indian Ayurvedic, and Indonesian Jamu traditional medicines, the fruit of this plant has been used as a bitter stomachic, a laxative, an antidiabetic, and an anthelmintic for children. Recently, the alcoholic extract from the fruit of M. charantia originated in Sri Lanka was reported to inhibit the increase of serum glucose in glucose-loaded rats.2) As chemical constituents of the fruit, many cucurbitane-type triterpene glycosides were reported, 3) but the constituents responsible for the inhibition of glucose absorption have not been identified. In the course of our studies on the bioactive constituents of medicinal foodstuffs, 1,4) we have also characterized many triterpene glycosides from the fruit of M. charantia originated in Japan, Thailand, Indonesia, India, and Sri Lanka. In this paper, we present the isolation and structure elucidation of goyaglycosides-a (1), -b (2), -c (3), -d (4), -e (5), -f (6), -g (7), and -h (8) and goyasaponins I (9), II (10), and III (11) from the fresh fruit of Japanese M. charantia, which is commonly called "nigauri" or "goya".The cucurbitane-and oleanene-type triterpene glycosides of the fresh fruit of Japanese M. charantia were separated by the procedures shown in Chart 1. The methanolic extract obtained from the fresh fruit of M. charantia was partitioned into an ethyl acetate and a water mixture to give an ethyl acetate extract and an aqueous phase. The aqueous phase was extracted with 1-butanol to furnish a 1-butanol extract and an aqueous extract. The 1-butanol extract was subjected to normal-and reversed-phase silica gel column chromatography and finally HPLC to give goyaglycosides-a

Inhibition of Increases in Blood Glucose and Serum Neutral Fat byMomordica charantiaSaponin Fraction

“…17) Since many saponin-rich plants are used for medicinal purposes, we prepared an MC saponin fraction and investigated the action mechanism of its blood glucose-and serum lipid-lowering effects.…”

Kuguacin J, a Triterpenoid from Momordica charantia Linn: A Comprehensive Review of Anticarcinogenic Properties

“…The cucurbitane-type triterpenoids and their aglycones have shown some biological effects beneficial in treating diabetes and obesity, and possess anticancer, anti-HIV and antifeedant properties [7,39]. More than fifty cucurbitacins and cucurbitane glycosides from the fruits, seeds, leaves, vines and stems have been reported [40][41][42][43][44][45][46][47][48]. Recently, Chen et al (2008) isolated and structured elucidation of nineteen cucurbitacins named kuguacins A-E from the roots of MC [49] and kuguacins F-S [50] from the vines and leaves of MC.…”

Cytotoxic Effect of Bitter Melon (Momordica charantia L.) Ethanol Extract and Its Fractions on Pancreatic Cancer Cells in vitro

“…8,13- 16 The extracts and juice of bitter melon contain high levels of glycosides (saponins), alkaloids, reducing sugars, resins, phenolic constituents, fixed oils and free acids. 17, 18 The bioactive components contributing these effects have so far been identified as ribosome inactivating proteins, other proteins (identified as MAP30, MCP30 and momordin), fatty acid alpha-eleostearic acid, and various triterpenoid compounds of the Cucurbitaceae family. The cytotoxic effect of various saponin compounds have also been explored in an array of different cancer cell lines in vitro, including colon, leukemia and breast cancers, with proposed mechanisms of action including inhibition of cell cycle signaling processes, initiation of apoptosis and degradation of the cytoskeleton.…”