Tirucallane Triterpenoid Saponins from Munronia delavayiFranch

Abstract

Four new tirucallane triterpenoid saponins, named munronosides I -IV (2 -5), along with three known triterpenoids, sapelin B (1), melianodiol, and (3b)-22,23-epoxytirucall-7-ene-3,24,25-triol, were isolated from the EtOH extract of the whole plants of Munronia delavayi Franch by chromatographic methods. On the basis of spectroscopic evidences, the structures of 2 -5 were elucidated as (20S,23R,24S)-21,25-epoxy-29-23-dihydroxytirucall-7-en-21-one (5). Introduction. -Plants of the family Meliaceae are a promising source of unique natural products for integrated pest management [1]. Plants of the genus Munronia are shrubs or half-shrubs which are naturally distributed in Sri Lanka, India, China, Indonesia, and from East Timor to the Philippines [2]. We previously studied Munronia henryi Harms collected from Xishuangbanna, in the south of Yunnan Province where the climate is warm and moist; many novel limonoids have been isolated, and some of them showed significant antifeedant properties [3]. Another species, Munronia delavayi Franch is narrowly distributed over the rocky area in the northeast of Yunnan Province. The markedly different plant habitats of the two species prompted us to investigate M. delavayi to see if the two plants differ in their secondary metabolites. Instead of limonoids as found in M. henryi, tirucallane triterpenoids, sapelin B (1) [4], melianodiol [5], (3b)-22,23-epoxytirucall-7-ene-3,24,25-triol [6], and four new tirucallane glycosides, munronosides I -IV (2 À 5) were isolated from the EtOH extract of M. delavayi Franch. This paper describes the isolation and structural determination of the new compounds.

Phytochemistry and Pharmacology of <i>Munronia</i> Genus (Meliaceae)

“…Surprisingly, 28 were the first record compound with the glucose moiety attached to C-21 position. From M. delavayi, munronin G (29) has been obtained by Cai and Luo [60]. Munronin G (29) showed same skeleton with munronolide (27), with the major difference was the presence of a furan ring in the side chain.…”

“…Qi et al [51] obtained 4α,7α-aromadendranediol (10), an aromadendrene-type sesquiterpenoid from M. henryi. Meanwhile, M. delavayi gave a simple diterpenoid compound, geranylgeraniol (11) isolated by Cai et al [60] from the whole plant of this species. Furthermore, Yan et al [61] reported the isolation and structural determination of a new diterpenoid, munronin R (12) from M. henryi.…”

“…All triterpenoid compounds isolated from this genus possessed a tirucallane-type triterpenoid. From ethanolic extract of whole plants M. delavayi, Cai et al [60] reported seven tirucallane-type triterpenoids, i.e. sapelin A (13), munronosides I-IV (14-17), melianodiol (18), and (3β)-22,23-epoxytirucall-7-ene-3,24,25-triol (19).…”

Chemical constituents from Munronia sinica and their bioactivities

“…1 Up to now, some phytochemical studies have been reported on M. delavayi [2][3][4][5] and M. henryi [6][7][8][9] , and tetranortriterpenoids and triterpenoids are their main components. Especially, tetranortriterpenoids exhibit chemical defensive function in nature, such as antibacterium, antifungal, 2 and antifeeding 8 activities.…”

Triterpenoids

“…A similar mixture of apotirucallanes, agladupols A-C 457-459, and tirucallanes, agladupols D 460 and E 461, was found in the leaves and stems of Aglaia duperreana. 243 Other new compounds include turrapubesols A-C 462-464 from Turrea pubescens, 244 munronosides I-IV from Munronia delavayi 245 with two new genins 465 and 466, and sapinmusaponins Q and R, with known genins, from the galls of Sapindus mukorossi. 246…”