Antidiabetic Activity and In Silico Molecular Docking of Polyphenols from Ammannia baccifera L. subsp. Aegyptiaca (Willd.) Koehne Waste: Structure Elucidation of Undescribed Acylated Flavonol Diglucoside.

Chemical investigation of the aerial parts of Ammania aegyptiaca ethanol extract (AEEE) showed high concentrations of polyphenol and flavonoid content, with notable antioxidant activity. Undescribed acylated diglucoside flavonol myricetin 3-O-ß-4C1-(6″-O-galloyl glucopyranoside) 7-O-ß-4C1-glucopyranoside (MGGG) was isolated from the aerial parts of AEEE, along with four known polyphenols that had not been characterized previously from AEEE. The inhibitory effects of MGGG, AEEE, and all compounds against α-amylase, pancreatic lipase and ß-glucosidase were assessed. In addition, molecular docking was used to determine the inhibition of digestive enzymes, and this confirmed that the MGGG interacted strongly with the active site residues of these enzymes, with the highest binding free energy against α-amylase (-8.99 kcal/mol), as compared to the commercial drug acarbose (-5.04 kcal/mol), thus justifying its use in the potential management of diabetes. In streptozotocin (STZ)-induced diabetic rats, AEEE significantly decreased high serum glucose, α-amylase activity and serum liver and kidney function markers, as well as increasing insulin blood level. Moreover, AEEE improved the lipid profile of diabetic animals, increased superoxide dismutase (SOD) activity, and inhibited lipid peroxidation. Histopathological studies proved the decrease in pancreas damage and supported the biochemical findings. These results provide evidence that AEEE and MGGG possess potent antidiabetic activity, which warrants additional investigation.

A Unique Acylated Flavonol Glycoside from Prunus persica (L.) var. Florida Prince: A New Solid Lipid Nanoparticle Cosmeceutical Formulation for Skincare.

Polyphenols are known dietary antioxidants. They have recently attracted considerable interest in uses to prevent skin aging and hyperpigmentation resulting from solar UV-irradiation. Prunus persica (L.) leaves are considered by-products and were reported to have a remarkable antioxidant activity due to their high content of polyphenols. This study aimed at the development of a cosmeceutical anti-aging and skin whitening cream preparation using ethanol leaves extract of Prunus persica (L.) (PPEE) loaded in solid lipid nanoparticles (SLNs) to enhance the skin delivery. Chemical investigation of PPEE showed significantly high total phenolic and flavonoids content with notable antioxidant activities (DPPH, ABTS, and ß-carotene assays). A unique acylated kaempferol glycoside with a rare structure, kaempferol 3-O-ß-4C1-(6″-O-3,4-dihydroxyphenylacetyl glucopyranoside) (KDPAG) was isolated for the first time and its structure fully elucidated. It represents the first example of acylation with 3,4-dihydroxyphenyl acetic acid in flavonoid chemistry. The in-vitro cytotoxicity studies against a human keratinocytes cell line revealed the non-toxicity of PPEE and PPEE-SLNs. Moreover, PPEE, PPEE-SLNs, and KDPAG showed good anti-elastase activity, comparable to that of N-(Methoxysuccinyl)-Ala-Ala-Pro-Val-chloromethyl ketone. Besides, PPEE-SLNs and KDPAG showed significantly (p < 0.001) higher anti-collagenase and anti-tyrosinase activities in comparison to EDTA and kojic acid, respectively. Different PPEE-SLNs cream formulae (2% and 5%) were evaluated for possible anti-wrinkle activity against UV-induced photoaging in a mouse model using a wrinkle scoring method and were shown to offer a highly significant protective effect against UV, as evidenced by tissue biomarkers (SOD) and histopathological studies. Thus, the current study demonstrates that Prunus persica leaf by-products provide an interesting, valuable resource for natural cosmetic ingredients. This provides related data for further studying the potential safe use of PPEE-SLNs in topical anti-aging cosmetic formulations with enhanced skin permeation properties.

Polyoxygenated flavonoids from Eugenia edulis.

Leaves of Eugenia edulis contain the new polyoxygenated flavonoid derivatives, gossypetin-3,8-dimethyl ether-5-O-beta-glucoside; gossypetin-3,5-dimethyl ether, and myricetin-3,5,3'-trimethyl ether. In addition, ten known polyphenolics were also isolated and identified. All structures were established on the basis of chemical and spectral evidence, including ESI-MS and 13C NMR.

Caffeoyl sugar esters and an ellagitannin from Rubus sanctus.

The new natural caffeoyl esters, 3,6-di-O-caffeoyl-(alpha/beta)-glucose and 1-O-caffeoyl-beta-xylose, together with the hitherto unknown natural tannin, 2,3-O-hexahydroxydiphenoyl-4,6-O-sanguisorboyl-(alpha/beta)-glucose, have been isolated from the aqueous alcohol aerial part extract of Rubus sanctus. Establishment of all structures was based on the chemical and spectral evidence, including ESI-MS and 2D NMR.