Safety Assessment of Camellia sinensis-Derived Ingredients As Used in Cosmetics

A botanical reference set illustrating a weight of evidence approach for skin sensitization risk assessment

Recent years have seen an increase in the use of botanicals and natural substances (BNS) in consumer products such as cosmetics and household care products. Most work conducted to date to assess botanicals for human safety has focused their use as dietary supplements and thus on systemic toxicity. However, the induction of skin sensitization is a possible adverse effect of natural products in particular those that come into skin contact, especially for cosmetics that remain on the skin and are not rinsed off following use. Assessments of BNS ingredients are often challenging for a number of reasons: the BNS are complex mixtures that can be of mostly unknown composition; the composition can be highly variable even within the same plant species and dependent on how processed; the physical form of the BNS raw material can vary from a highly concentrated powdered extract to a liquid extract containing only a small percentage of the BNS; testing of the BNS raw materials in New Approach Methods (NAM) has uncertainty as these methods are often not developed or validated for complex mixtures. In this study, a reference set of 14 selected BNS which span the range of skin sensitization potential was complied. These data were used in a Weight of Evidence (WoE) approach to evaluate their skin sensitization potential with each of the data rich BNS being classified as either having strong evidence of inducing skin sensitization based on human topical use history, animal data, clinical data, composition data and NAM data, or having some but more limited (weak) evidence of inducing skin sensitization, or having strong evidence of no skin sensitization potential. When available data have sufficient potency related information, sensitization potency assessment is also provided based on WoE, classifying these BNS as either strong, moderate, or weak sensitizers, or non-sensitizers. An outline for a BNS skin sensitization risk assessment framework is proposed starting with exposure-based waiving and WoE assessment for higher exposures. In addition to demonstrating the application of the WoE approach, the reference set presented here provides a set of 'data rich' botanicals which cover a range of sensitization potencies that could be used for evaluating existing test methods or aid in the development of new predictive models for skin sensitization.

Recent insights into catechins-rich Assam tea extract for photoaging and senescent ageing

Tea (Camellia spp.) is an important medicinal herb. C. sinensis var. sinensis is the most studied tea variety due to its more preferred flavor than C. sinensis var. assamica (Assam tea), the less economic importance with more bitter variety. A bitter taste highlights its potential as a candidate source for tea catechins, the health beneficial actives applicable for ageing treatment. Nonetheless, indicative data for tea on UV-induced and senescent ageing remain unclarified. Assam tea extract (ATE) was prepared and standardized in terms of TPC, TFC and TTC. EGCG was HPLC quantified as the prime ATE catechin. In vitro antioxidant activity of ATE was exhibited with ABTS, DPPH and FRAP assays. ATE's cellular antioxidant activity was indicated in HDFs at a stronger degree than ascorbic acid. The photoaging protection of ATE was evidenced in a coculture of HaCaT cells and HDFs. ATE markedly suppressed UV-induced IL-6, IL-8, MMP-1 and MMP-9 expressions. The proficiency of ATE targeting on senescent ageing was demonstrated in an ex vivo human skin model, where IL-6 and MMP-1 expressions were suppressed, whilst hyaluronic acid and collagen syntheses were promoted. ATE was chemically stabled as indicated by the catechin contents and color parameters following 6 months storage under conditions recommended for topical product. ATE enriched in catechins warrants its applicability as a new generation of photoaging protectant agent promising for the prevention and treatment for senescent ageing. The findings indicate the proficiency of ATE for innovative anti-ageing agent.

A Preliminary Study on the Release of Bioactive Compounds from Rice Starch Hydrogels Produced by High-Pressure Processing (HPP)

This work aimed to carry out a preliminary study on the release of bioactive compounds loaded into starch-based hydrogels produced by high-pressure processing (HPP). As a study case, the experiments were carried out on rice starch HPP hydrogels. Rice starch (20% w/w) and green tea extract (2% w/w), suspended in distilled water, were treated by HPP at processing conditions enabling starch gelatinisation, namely 600 MPa for 15 min at room temperature. Additional experiments were carried out on samples that were further loaded with glycerol (5% w/w). Gel formation was assessed by analysing the gelatinisation extent, structuring level, and swelling power of the samples. At the processing conditions utilised, stable hydrogels were obtained even in the presence of the extract and/or the glycerol in the starch suspension. As expected, the colour of the hydrogels formed was affected by the addition of green tea extract in the starch solution. HPP starch hydrogels were characterised by Fourier transform infrared spectroscopy (FT-IR) to determine the interactions between the different compounds utilised in the formulation. Moreover, the release kinetics of bioactive compounds from HPP rice starch hydrogels was evaluated using a vertical Franz diffusion cells system, simulating a transdermal pattern. The diffusion of bioactive compounds was measured spectrophotometrically and via HPLC analysis. A controlled release of bioactive compounds from the hydrogel structure was detected, suggesting that small molecules, such as polyphenols, positively interacted with the rice starch HPP hydrogel network that allowed a smooth and constant release of these bioactive compounds over time.

Therapeutic potential of natural molecules against Alzheimer's disease via SIRT1 modulation

Alzheimer's disease (AD) is a neurodegenerative disease mainly characterized by progressive cognitive dysfunction and memory impairment. Recent studies have shown that regulating silent information regulator 1 (SIRT1) expression has a significant neuroprotective effect, and SIRT1 may become a new therapeutic target for AD. Natural molecules are an important source of drug development for use in AD therapy and may regulate a wide range of biological events by regulating SIRT1 as well as other SIRT1-mediated signaling pathways. This review aims to summarize the correlation between SIRT1 and AD and to identify in vivo and in vitro studies investigating the anti-AD properties of natural molecules as modulators of SIRT1 and SIRT1-mediated signaling pathways. A literature search was conducted for studies published between January 2000 and October 2022 using various literature databases, including Web of Science, PubMed, Google Scholar, Science Direct, and EMBASE. Natural molecules, such as resveratrol, quercetin, icariin, bisdemethoxycurcumin, dihydromyricetin, salidroside, patchouli, sesamin, rhein, ligustilide, tetramethoxyflavanone, 1-theanine, schisandrin, curcumin, betaine, pterostilbene, ampelopsin, schisanhenol, and eriodictyol, have the potential to modulate SIRT1 and SIRT1 signaling pathways, thereby combating AD. The natural molecules modulating SIRT1 discussed in this review provide a potentially novel multi-mechanistic therapeutic strategy for AD. However, future clinical trials need to be conducted to further investigate their beneficial properties and to determine the safety and efficacy of SIRT1 natural activators against AD.

Assessment of Cosmeceutical Potentials of Selected Mushroom Fruitbody Extracts Through Evaluation of Antioxidant, Anti-Hyaluronidase and Anti-Tyrosinase Activity

Cosmeceutical formulations containing naturally derived active ingredients are currently preferred by consumers worldwide. Mushrooms are one of the potential sources for cosmeceutical ingredients but relevant research is still lacking. In this study, hot- and cold-water extractions were performed on four locally-cultivated mushrooms—Pleurotus ostreatus, Ganoderma lucidum, Auricularia polytricha and Schizophyllum commune—with the aim to assess the cosmeceutical potential of these mushroom fruitbody extracts. Total phenolics, polysaccharide and glucan content were determined. Antioxidant property of the mushroom extracts was assessed by determining the DPPH radical scavenging, ferric-reducing (FRAP) and superoxide anion (SOA) scavenging activity. Anti-hyaluronidase activity was used as an indicator for the anti-aging and anti-inflammatory property, while anti-tyrosinase activity was evaluated to assess the anti-pigmentation or whitening property of these extracts. Our results showed that total polysaccharide content of P. ostreatus extracts was the highest (235.8–253.6 mg GE/g extract), while extracts from G. lucidum contained the lowest glucan (10.12–10.67%). Cold-water extract from S. commune exhibited substantial tyrosinase inhibition activity (98.15%) and SOA scavenging activity (94.82%). The greatest hyaluronidase activity was exhibited by G. lucidum hot-water extract, with the value of 72.78%. The findings from the correlation analyses suggest that the cosmeceutical properties of these mushrooms can be attributed mainly to the combination of different types of compound such as polysaccharides and phenolics. Overall, cold-water extract of S. commune and hot-water extract of G. lucidum showed the best results and may be further investigated.