Glycosides of benzyl and salicyl alcohols from Alangium chinense

New phenylpropanoid-substituted and benzyl-substituted flavonols from Alangium chinense

Two previously undescribed flavonols with phenylpropanoid or benzyl substitution, named alangsine A (1), and alangsine B (2), together with four known compounds (3-6) were isolated from the leaves of Alangium chinense. Alangsine A was a racemic mixture, which was further separated into two enantiomers via high-performance liquid chromatography on a chiral column. The absolute configurations of the enantiomer pairs were deduced from the circular dichroism (CD) spectra. The activity of the isolated compounds towards neuronal excitability was examined.

Genus Alangium - A review on its traditional uses, phytochemistry and pharmacological activities

The species from Alangium have been used as folk medicine to treat rheumatism, skin diseases, diabetes by the people of Southeast Asia. Previous phytochemical studies have shown this genus are rich sources of alkaloids, glycosides, and terpenoids, which have attracted considerable attention of many researchers due to their markedly diverse and complex architecture. The crude extracts as well as the monomeric compounds from the title genus possess anti-tumor, anti-inflammatory, antibacterial, anti-oxidant pharmacological activities. Besides, some isolates from Alangium exhibited the effects on skeletal, smooth muscle and the nervous system. As a large genus of medicinal plants, the medicinal value of Alangium has been widely reported, but there is no review that provide a systematic summary towards its chemical constituents and pharmacological activities, to our knowledge. This work aims to present a comprehensive overview on the traditional uses, phytochemistry, and pharmacological activities of medicinal plants in the genus Alangium, and to explore the evidence supporting its ethnopharmacological effectiveness.

A Review of Common Medicinal Plants in Chin State, Myanmar

Promising sources of novel bioactive compounds include plants growing in several third-world countries where the local flora is still largely uninvestigated. A paradigmatic example is represented by medicinal plants growing in Myanmar, especially in Chin State, in northwestern Myanmar. This is one of the least developed areas of the country where the people still use natural remedies derived from a rich biodiversity. This review mainly covers the investigations done on phytochemical constituents and biological activities of 20 medicinal plants, namely Alangium chinense, Anemone obtusiloba, Anneslea fragrans, Antidesma bunius, Croton oblongifolius, Embelia tsjeriam-cottam, Ficus heterophylla, Gaultheria fragrantissima, Hydnocarpus kurzii, Leea macrophylla, Leucas cephalotes, Millingtonia hortensis, Myrica nagi, Olax scandens, Pimpinella heyneana, Pterospermum semisagittatum, Ruellia tuberosa, Smilax zeylanica, Stemona burkillii, and Tadehagi triquetrum, that have long been used in the Chin State for curing various diseases. These plants have been selected on the basis of their medicinal uses not only in Myanmar but also in the related Ayurvedic healing system. Moreover, besides their medicinal importance, most of them grow in the Chin State more abundantly than in other regions of Myanmar. Although the efficacy of some of these plants have been verified scientifically, the chemical constituents and biological activities of most of them still need to be investigated to confirm the claimed therapeutic effects.

Evaluation of the antioxidant and anti-osteoporosis activities of chemical constituents of the fruits of Prunus mume

The present study investigated the antioxidant and anti-osteoporosis activities of phytochemicals in the fruits of Prunus mume. From the methanol extract, three new acylated sucroses, mumeoses P-R (1-3), were isolated together with 20 known compounds (4-23). Compounds 1-3 showed potent peroxyl radical-scavenging activities and 12-19 showed both potent peroxyl radical-scavenging and reducing activities. The anti-osteoporosis activity was evaluated using murine pre-osteoblastic MC3T3-E1 cells and pre-osteoclastic RAW 264.7 cells. Compounds 2 and 3 (cis-trans isomers), 5, 7, 8, and 10 significantly stimulated the differentiation of pre-osteoblastic MC3T3-E1 cells to increase collagen synthesis or mineralization functions of osteoblasts, while compounds 5, 6, 9, 10, 12, 14-16, 18, 20, and 22 significantly suppressed tartrate-resistant acid phosphatase activity in receptor activator of nuclear factor-κB ligand-induced osteoclastic RAW 264.7 cells. These results indicated that the fruits of P. mume are an excellent source of antioxidant and anti-osteoporosis phytochemicals.

Astonishing diversity of natural surfactants: 5. Biologically active glycosides of aromatic metabolites

This review article presents 342 aromatic glycosides, isolated from and identified in plants and microorganisms, that demonstrate different biological activities. They are of great interest, especially for the medicinal and/or pharmaceutical industries. These biologically active natural surfactants are good prospects for the future chemical preparation of compounds useful as antioxidant, anticancer, antimicrobial, and antibacterial agents. These glycosidic compounds have been classified into several groups, including simple aromatic compounds, stilbenes, phenylethanoids, phenylpropanoids, naphthalene derivatives, and anthracene derivatives.

Chemoenzymatic Synthesis of Naturally Occurring Benzyl 6-O-Glycosyl-.BETA.-D-glucopyranosides

Direct beta-glucosidation between benzyl alcohol and D-glucose (5) using the immobilized beta-glucosidase from almonds with the synthetic prepolymer ENTP-4000 gave a benzyl beta-D-glucoside (1) in 53% yield. The coupling of the benzyl beta-D-glucopyranoside congener (8) derived from 1 with phenyl 2,3,4-tri-O-acetyl-1-thio-beta-D-xylopyranoside (9), ethyl 2,3,4-tri-O-acetyl-1-thio-alpha-L-rhamnopyranoside (13), and 2,3,4-tri-O-acetyl-alpha-L-arabinopyranosyl bromide (15) afforded 10, 14, and 16, respectively, as coupled products. Deprotection of 10, 14, and 16 provided the synthetic benzyl beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside (2), benzyl alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (3), and benzyl alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside (4), respectively.

Enzymatic synthesis of two salicin analogues by reaction of salicyl alcohol with Bacillus macerans cyclomaltodextrin glucanyltransferase and Leuconostoc mesenteroides B-742CB dextransucrase

Beta-Salicin is a naturally occurring glycoside found in the bark of poplar and willow trees. Ancient man used it as an analgesic and antipyretic. It has a D-glucopyranose unit attached by a beta-linkage to the phenolic hydroxyl of salicyl alcohol. Two new salicin analogues have been enzymatically synthesized by transglycosylation reactions: (a) by the reaction of Bacillus macerans cyclomaltodextrin glucanyltransferase with cyclomaltohexaose and salicyl alcohol, followed by reactions with alpha amylase and glucoamylase to give D-glucopyranose attached by an alpha-linkage to the phenolic hydroxyl of salicyl alcohol as the major product, alpha-salicin; and (b) by the reaction of Leuconostoc mesenteroides B-742CB dextransucrase with sucrose and salicyl alcohol, followed by reactions with dextranase and glucoamylase to give alpha-d-glucopyranose attached to the primary alcohol hydroxyl of salicyl alcohol as the major product, alpha-isosalicin.