Cosmeceuticals are the fastest growing products in the cosmetics field and represent a hybrid between cosmetics and drugs. The main benefits reported for cosmeceutical herbal extracts, used in skin care, include antioxidant and antimicrobial activities and the tyrosinase inhibiting effect. The aim of this study was to evaluate the antioxidant and antibacterial activities of extracts from Chromolaena odorata, Mitracarpus villosus, Senna alata, Tetradenia riparia, Cannabis sativa and Pterocarpus soyauxii used traditionally in the management of skin and skin annexes pathologies; additionally to determine their microscopical characteristics and their chromatographic fingerprints. Microscopic analyses showed the specific botanical microscopic characters for each plant that constitute the database useful for the identification and authentication of these botanicals. To the best of our knowledge, our work is the first to describe the microscopic histological characters of studied plants except for Cannabis sativa. The results of the TLC chromatographic analysis

The meta hybrid M06-2X functional combined with the 6-311++G(d,p) basis set are used to investigate the antioxidant activity of five benzoic acid derivatives naturally occurring in several plant food: gallic acid, para-hydroxybenzoic acid, protocatechuic acid, syringic acid and vanillic acid. To assess the antioxidant properties of these compounds, three mechanisms of free radicals scavenging are considered, namely the hydrogen atom transfer (HAT), stepwise electron transfer proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) models. The effect of polar environments on the antioxidant power of these compounds is mimicked in water and methanol using the IEF-PCM solvation method. Our findings suggest that HAT is the preferred mechanistic pathway in gas phase, while SPLET is favoured in polar mediums. Protocatechuic and gallic acids are the most active in gas and polar solutions respectively, whereas PHBA is the least active in all the environments considered. The O-H group in para position of the carboxylic group (O3-H for GA and O2-H for the rest) is confirmed to be the most reactive site in gas phase, while in solution it is either of the O1-H site (for PHBA, PCA, SA and VA) or O4-H groups (for GA). The “HOMO-rule” of free radical scavenging ability does not seem to account properly for the antioxidant properties of this set of chemicals.

This study reports a computational investigation on the antioxidant activity of five plant food benzoic acid derivatives, namely gallic acid (GA), para-hydroxybenzoic acid (PHBA), protocatechuic acid (PCA), syringic acid (SA), and vanillic acid (VA). Based on computed thermodynamics parameters, a detailed comparative debate is developed concerning their free radical scavenging activity in the gas phase and polar solutions (in water and methanol solvents). This discussion goes on to elucidate both the most preferred mechanism and the order of antioxidant activity for these molecules in each environment. Paradoxically, calculations using the harmonic oscillator model of aromaticity (HOMA) suggest that H abstraction radicals gain in stability as the central benzene ring loses in structural aromaticity. Finally, spin densities and fukui function f0 seem to be good indicators of the local reactivity of these compounds towards free radicals.