Six new polyhydroxysteroidal glycosides, anthenosides S1  - S6 (1 - 6), along with a mixture of two previously known related glycosides, 7 and 8, were isolated from the methanolic extract of the starfish Anthenea sibogae. The structures of 1 - 6 were established by NMR and HR-ESI-MS techniques as well as by chemical transformations. All new compounds have a 5α-cholest-8(14)-ene-3α,6β,7β,16α-tetrahydroxysteroidal nucleus and differ from majority of starfish glycosides in positions of carbohydrate moieties at C(7) and C(16) (1 - 4, 6) or only at C(16) (5). The 4-O-methyl-β-d-glucopyranose residue (2) and Δ -cholestane side chain (3) have not been found earlier in the starfish steroidal glycosides. The mixture of 7 and 8 slightly inhibited the proliferation of human breast cancer T-47D cells and decreased the colony size in the colony formation assay.

A new steroidal glycoside called planciside D was isolated from the tropical starfish Acanthaster planci and assigned the structure (. Planciside D was a triglycoside containing two carbohydrate chains, which are rarely found in starfish. Its structure was established using 2D NMR spectroscopy and tandem mass spectrometry with electrospray ionization (ESI).Keywords: starfish, Acanthaster planci, glycoside, steroidal aglycon, NMR spectroscopy.Glycosides of polyhydroxysteroids and asterosaponins are the most common structural groups of starfish steroidal metabolites [1-6]. Glycosides of polyhydroxysteroids contain a highly oxidized aglycon with 3-10 hydroxyls and one, two, or rarely three monosaccharide residues located on C-3 (or C-15) of the steroid core and/or in the C-24 or C-26, C-28, and C-29 positions of the aglycon side chain. Asterosaponins are oligoglycosides containing, as a rule, a 3-O-sulfated ' 9(11) -3E,6D-dihydroxysteroidal aglycon and a carbohydrate chain of 5-6 monosaccharide residues located on C-6 of the aglycon. Starfish steroidal glycosides are usually found in extracts as complicated mixtures that are difficult to separate into the pure compounds. The majority of the minor components of these fractions are unstudied although certain biosynthesis features of them or other metabolites are related to their formation. Starfish steroidal glycosides are interesting not only because of their unusual chemical structures but also because of their broad spectra of biological properties, including embryotoxic, antifungal, antiviral, antibacterial, neuroprotective, and other types of activity [1-6].The starfish Acanthaster planci L. 1758 (Order Valvatida, Family Acanthasteridae) is distributed in tropical waters of the Indian and Pacific Oceans and preys primarily on reef-forming coral polyps. A. planci is one of the largest starfish and is known also by the name "crown of thorns" because its body is covered with numerous long sharp needles. The toxic properties of needles from this starfish are often associated with the presence of polar steroidal glycosides, mainly asterosaponins, in its tissues [1]. Polar steroidal compounds from A. planci were studied earlier by Japanese and Italian researchers.

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In our research on biologically active compounds from Vietnamese marine invertebrates, rare melibiose‐containing glycosphingolipids were found in a sample of a sponge‐coral association (Desmapsamma anchorata/Carijoa riisei). Melibiosylceramides were analyzed as constituents of some multi‐component RP‐HPLC fractions, and the structures of 14 new (1b, 3b, 4a–4c, 6a–6c, 8b, 9a, 9b, 10b, 11a, 11b) and five known (2b, 5a–5c, 7b) natural compounds were elucidated using NMR, mass spectrometry, optical rotation, and chemical transformations. These α‐d‐Galp‐(1→6)‐β‐d‐Glcp‐(1 1)‐ceramides (presumably sponge‐derived compounds) were shown to contain phytosphingosine‐type n‐t17:0 (1), (6E)‐n‐t17:1 (2), i‐t17:0 (3), n‐t18:0 (4), (6E)‐n‐t18:1 (5), i‐t18:0 (6), (6E)‐i‐t18:1 (7), i‐t19:0 (8), (6E)‐i‐t19:1 (9), ai‐t19:0 (10), and (6E)‐ai‐t19:1 (11) backbones N‐acylated with saturated straight‐chain (2R)‐2‐hydroxy C21 (a), C22 (b), and C23 (c) acids. Characteristic trends in the fragmentations of the terminal parts of tetraacetylated normal‐chain and iso‐ and anteiso‐branched sphingoid bases were observed using GC/MS. The total sum of melibiosylceramides and compound 5b caused a reduction in colony formation of human melanoma cells.

A new cucurbitane-type glycoside (1) and two known compounds (2-3) were isolated from the ethanol extract of the fruits of Momordica charantia L. Their chemical structures were determined as (19 S,23 E)-5 β­,19-epoxy-19-methoxycucurbita-6,23-diene-3 β,25-diol 3 -O-β-D-allopyranoside (1), goyaglycoside d (2), and (19 S,23 E)-5 β,19-epoxy-19-methoxycucurbita-6,23-diene-3 β,25-diol (3) on the basis of the extensive spectroscopic methods, including 1D, 2D NMR, HRESIMS, and in comparison with the reported data. Compounds 1 to 3 were evaluated for α-glucosidase inhibitory effects. Compounds 1 and 2 showed anti α-glucosidase activity with IC50 values of 134.12 ± 11.20 and 163.17 ± 13.71 µM, respectively, compared with the positive control, acarbose, IC50 160.99 ± 14.30 μM. Compounds 2 and 3 were first isolated from plant M. charantia growing in Vietnam.

Đại học Sư phạm, Đại học Thái Nguyên TÓM TẮT: Kết quả điều tra của chúng tôi đã thống kê được 121 loài thực vật thuộc 110 chi, 65 họ của 4 ngành thực vật bậc cao có mạch. Thành phần dạng sống chủ yếu của thực vật tại khu vực là các cây thân gỗ, thân bụi, thân thảo và thân leo. Trong đó, dạng thân gỗ và thân thảo chiếm tỷ lệ cao hơn nhất (41,3% và 30,6%). Giá trị sử dụng của thực vật gồm các nhóm sau: nhóm cây cho gỗ chiếm 28,9%, nhóm làm thuốc chữa bệnh chiếm 75%, nhóm cây ăn được (gồm cây cho quả và rau rừng) chiếm 19%, nhóm làm cảnh chiếm 8,3%, nhóm cho tinh dầu chiếm 9,1%. Hiện tại, nguồn tài nguyên thực vật đang bị người dân khai thác quá mức và có nguy cơ bị cạn kiệt, vì vậy cần phải có những biện pháp bảo tồn đối với nguồn tài nguyên này. Từ khóa: Bảo tồn, dạng sống, tài nguyên thực vật, Thái Nguyên.

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Two new pregnane glycosides were isolated from the leaves of Gymnema sylvestre (Retz.) R.Br. ex Sm. Their chemical structures were determined as (20 S)−12 β-tigloyloxy-5 α-hydroperoxy-3 β,8 β,14 β,17 β,20-pentahydroxypregn-6-ene 3- O-β-D-glucopyranosyl-(1→4)‐6-deoxy-3- O-methyl- β-D-allopyranosyl-(1→4)- β-D-oleandropyranosyl-(1→4)- β-D-cymaropyranosyl-(1→4)- β-D-cymaropyranoside (1) and (20 S)−12 β-benzoyloxy-5 α-hydroperoxy-3 β,8 β,14 β,17 β,20-pentahydroxypregn-6-ene 3- O-β-D-glucopyranosyl-(1→4)‐6-deoxy-3- O-methyl- β-D-allopyranosyl-(1→4)- β-D-oleandropyranosyl-(1→4)- β-D-cymaropyranosyl-(1→4)- β-D-cymaropyranoside (2) on the basis of the extensive spectroscopic methods, including 1D, 2D NMR, HRESIMS, and in comparison with the reported data. At the concentration of 200 µM, compounds 1 and 2 showed moderate anti α-glucosidase and α-amylase activities with inhibitory percentage of 31.1 ± 1.2 and 42.3 ± 1.7% (for α-glucosidase), and 27.8 ± 1.3 and 34.5 ± 1.5% (for α-amylase), respectively.