Aloe juvenna Brandham & S.Carter as α-Amylase Inhibitor and Hypoglycaemic Agent with Anti-inflammatory Properties for Diabetes Management.

Despite Aloe's traditional use, Aloe juvenna Brandham & S.Carter is poorly characterized. Other Aloes are known for their antidiabetic activity. This study describes the antidiabetic potentials and phytoconstituents of the A. juvenna leaves methanolic extract (AJME). Twenty-six phytoconstituents of AJME were described using HPLC/MS-MS. Lupeol and vitexin were isolated using column chromatography. The antidiabetic activity of AJME was investigated using an in vivo high-fat diet/streptozotocin-induced diabetic rat model and in vitro α-glucosidase and α-amylase inhibitory activity assays. AJME demonstrated its α-amylase inhibitory activity (IC50=313±39.9 ppm) with no effect on α-glucosidase. In vivo, AJME dose-dependently improved hyperglycaemia in a high-fat diet/streptozotocin-induced diabetic rat model. Notably, the higher dose (1600 mg/kg) of AJME significantly downregulated serum interleukin-6, tumor necrosis factor-α, and matrix metalloproteinase-1 genes, suggesting its anti-inflammatory effect. These findings indicate AJME's potential as a significant antidiabetic agent through its α-amylase inhibition, hypoglycaemic, and anti-inflammatory properties.

Echinocystic acid 3,16-O-bisglycosides from Albizia procera.

Three triterpene glycosides and two known ones were isolated from the bark of Albizia procera by using chromatographic techniques. The structures of the compounds were determined to be 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 16-O-beta-D-glucopyranoside, 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 16-O-beta-D-glucopyranoside and 3-O-alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 16-O-beta-D-glucopyranoside. Their structures were determined by NMR techniques including HOHAHA, (1)H-(1)H COSY, ROE, HMQC and HMBC experiments together with FABMS as well as acid hydrolysis. To the best of our knowledge, the new compounds are considered the first examples of echinocystic acid 3,16-O-bisglycosides. In contrast to other cytotoxic echinocystic acid glycosides with N-acetyl glucosamine unit, the new glycosides were found inactive when assayed by MTT method for their cytotoxicities against the human tumor cell lines HEPG2, A549, HT29 and MCF7. The results showed the importance of the free hydroxyl group at the aglycone C-16 for exhibiting cytotoxic properties.

Triterpenoid saponins with N-acetyl sugar from the bark of Albizia procera.

Three (1,2,4) and one known (3) triterpenoid saponins were isolated from the bark of Albizia procera. The saponins were characterized as 3-O-[beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl] echinocystic acid (1), 3-O-[alpha-L-arabinopyranosyl-(1-->2)-beta-D-fucopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl] echinocystic acid (2) and 3-O-[beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosyl] acacic acid lactone (4). Their structures were elucidated by 1D and 2D NMR experiments, FABMS as well as chemical means. Saponins 1 and 3 exhibited cytotoxicity against HEPG2 cell line with IC50 9.13 microg/ml and 10 microg/ml, respectively.