Structures of breynins A and B, architecturally complex, hypocholesterolemic spiroketal glycosides. A revised formulation of breynin B

Chromatographic Separation of Breynia retusa (Dennst.) Alston Bark, Fruit and Leaf Constituents from Bioactive Extracts

Breynia retusa (Dennst.) Alston (also known as Cup Saucer plant) is a food plant with wide applications in traditional medicine, particularly in Ayurveda. Extracts obtained with four solvents (dichloromethane, methanol, ethyl acetate and water), from three plant parts, (fruit, leaf and bark) were obtained. Extracts were tested for total phenolic, flavonoid content and antioxidant activities using a battery of assays including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), total antioxidant capacity (TAC) (phosphomolybdenum) and metal chelating. Enzyme inhibitory effects were investigated using acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase as target enzymes. Results showed that the methanolic bark extract exhibited significant radical scavenging activity (DPPH: 202.09 ± 0.15; ABTS: 490.12 ± 0.18 mg Trolox equivalent (TE)/g), reducing potential (FRAP: 325.86 ± 4.36: CUPRAC: 661.82 ± 0.40 mg TE/g) and possessed the highest TAC (3.33 ± 0.13 mmol TE/g). The methanolic extracts were subjected to LC-DAD-MSⁿ and NMR analysis. A two-column LC method was developed to separate constituents, allowing to identify and quantify forty-four and fifteen constituents in bark and fruits, respectively. Main compound in bark was epicatechin-3-O-sulphate and isolation of compound was performed to confirm its identity. Bark extract contained catechins, procyanidins, gallic acid derivatives and the sulfur containing spiroketal named breynins. Aerial parts mostly contained flavonoid glycosides. Considering the bioassays, the methanolic bark extract resulted a potent tyrosinase (152.79 ± 0.27 mg kojic acid equivalent/g), α-amylase (0.99 ± 0.01 mmol acarbose equivalent ACAE/g) and α-glucosidase (2.16 ± 0.01 mmol ACAE/g) inhibitor. In conclusion, methanol is able to extract the efficiently the phytoconstituents of B. retusa and the bark is the most valuable source of compounds.

Two new glycosides from Breynia vitis-idaea

A new sulfur-containing spiroketal glycoside, breynin I (1), and a new terpenic glycoside, breyniaionoside E (2), together with 10 known compounds, were isolated from the aerial parts of Breynia vitis-idaea (Euphorbiaceae), a traditional Chinese medicine used for the treatment of chronic bronchitis and wounds. Their structures were elucidated on the basis of spectroscopic analysis and modified Mosher's method.

Glycosides from Breynia fruticosa and Breynia rostrata

Glycosides, 3-acetyl-(-)-epicatechin 7-O-beta-glucopyranoside (1), 3-acetyl-(-)-epicatechin 7-O-(6-isobutanoyloxyl)-beta-glucopyranoside (2), 3-acetyl-(-)-epicatechin 7-O-[6-(2-methyl-butanoyloxyl)]-beta-glucopyranoside (3), (5Z)-6-[5-(2-hydroxypropan-2-yl)-2-methyl-tetrahydrofuran-2-yl]-3-methylhexa-1,5-dien-3-O-beta-glucopyranoside (4), hydroquinone O-[6-(3-hydroxyisobutanoyl)]-beta-galactopyranoside (5), 4-(4-O-beta-glucopyranosyl-phenoxy)-1-O-beta-glucopyranosyl-1,3-benzenediol (6), 7,8-erythro-dihydroxy-3,4,5-trimethoxy-phenyl-propane8-O-beta-glucopyranoside (7), 6,7-dimethylbenzofuranol 5-O-beta-xylopyranosyl-(1-->6)-beta-glucopyranoside (8), along with 30 known glycosides, were isolated from Breynia fruticosa and Breynia rostrata (Euphorbiaceae). Their structures were determined on the basis of spectroscopic analysis and chemical methods.