Three New Pentacyclic Triterpenoids from Centella asiatica

Abstract

Three new pentacyclic triterpenoids, named centellasaponin I (1), centellasaponin J (2), and centellasaponin E (3), together with three known compounds, were isolated from the whole plants of Centella asiatica. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D‐ and 2D‐NMR and HR‐MS experiments, and by comparison with literature data.

Oleanane- and Ursane-Type Triterpene Saponins from Centella asiatica Exhibit Neuroprotective Effects

“…The absolute configurations of the sugar residues were determined to be D-glucose and L-rhamnose by the method previously reported. 16 The 1 H and 13 C NMR spectra of compound 1 resembled those of asiaticoside B (8), except for the presence of two double bonds in compound 1. The absorption band at 284 nm in the UV spectrum indicated that these two double bonds were conjugated, 19 which were further confirmed to be located at Δ 9,11 1 and 2) of compound 2 resembled those of compound 1 for rings A−D and the sugar residues.…”

“…Compound 4, a white powder, showed a HRESIMS peak at m/z 989.4960 [M + H] + , suggesting a molecular formula of C 48 H 76 O 21 . By comparison of the 13 C and 1 H NMR data (Tables 1 and 2) of compound 4 to those of compound 3, it was easy to conclude that the differences between these two compounds were the same as those between compounds 1 and 2, indicating that compound 4 bore a ursane-type aglycone. Extensive analysis of the DEPT, 1 H− 1 H COSY, HSQC, NOESY, and HMBC spectra further confirmed the structure of compound 4 as 2α,3β,6β,23-tetrahydroxy-11-oxo-urs-12-ene-28-oic acid 28-O-α-L-rhamnopyranosyl(1→4)-β-Dglucopyranosyl(1→6)-β-D-glucopyranoside, named 11-oxo-madecassoside.…”

“…The absorption band at 284 nm in the UV spectrum indicated that these two double bonds were conjugated, 19 which were further confirmed to be located at Δ 9,11 1 and 2) of compound 2 resembled those of compound 1 for rings A−D and the sugar residues. A comparison of the differing 13 C NMR data for ring E between compounds 1 and 2 to those between centellasaponin G and centellasaponin H evidenced that compound 2 possessed an ursane-type aglycone rather than an oleanane-type aglycone in compound 1, 12 which was further verified by the cross peaks between H-29 (δ H 0.90) and C-18 (δ C 51.6) and between H-30 (δ H 0.84) and C-21 (δ C 30.8) in the HMBC spectrum. The above evidence, along with the distortionless enhancement by polarization transfer (DEPT) and heteronuclear single-quantum correlation (HSQC) data, defined the structure of compound 2 as 2α,3β,6β,23tetrahydroxyurs-9,12-diene-28-oic acid 28-O-α-L- 1 and 2) of compound 3 closely resembled those of asiaticoside B (8), except that a methylene group in compound 8 was replaced by a carbonyl group in compound 3.…”

“…C. asiatica is rich in triterpene saponins chiefly composed of oleanolic- and ursolic-acid-based glycosides, accounting for around 8% of the dry weight of this herb. − However, previous pharmaceutical studies mainly focused on the neuroprotective actions of the crude extract and several main components from C. asiatica .…”

Biologically active compounds of plant origin in medicine

“…Słowa kluczowe: tymianek, rozmaryn, szałwia, majeranek, oregano, bazylia, fenolowe przeciwutleniacze [Zainol et al 2003]. Given its content of various biologically active substances, the species has been used in the pharmaceutical [Mala andTulika 2015, Roy andBharadvaja 2017], cosmetic [Singh-Verma 2002], and food industries as a food additive [Hashim et al 2011]. The aim of the study was to present bioactive substances identified in Centella asiatica (L.) Urb.…”