Astaxanthin is a potent antioxidant compared with vitamins and other antioxidants. However, astaxanthin extract from shrimp processing waste has not yet been used in cosmetic products. This study aimed to explore the natural astaxanthin from shrimp shells for antioxidant and antityrosinase activities as well as potential toxicity. The antioxidant activities were performed with 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, β-carotene bleaching, and singlet oxygen quenching assays. The results revealed that astaxanthin extract demonstrated potent antioxidant activities against DPPH and ABTS radicals, and prevented the bleaching of β-carotene and quenching of singlet oxygen (EC50 17.5 ± 3.6, 7.7 ± 0.6, 15.1 ± 1.9 and 9.2 ± 0.5 μg/mL, respectively). Furthermore, the astaxanthin extract could inhibit tyrosinase activity (IC50 12.2 ± 1.5 μg/mL) and had no toxic effects on human dermal fibroblast cells. These results suggested that shrimp astaxanthin would be a promising dietary supplement for skin health applications.
Lansium domesticum Corr. or “long-kong” is one of the most popular fruits in Thailand. Its peel (skin, SK) and seeds (SD) become waste unless recycled or applied for use. This study was undertaken to determine the bioactivity and phytochemical components of L. domesticum (LD) skin and seed extracts. Following various extraction and fractionation procedures, 12 fractions were obtained. All fractions were tested for antioxidant capacity against O2−• and OH•. It was found that the peel of L. domesticum fruits exhibited higher O2−• and OH• scavenging activity than seeds. High potential antioxidant activity was found in two fractions of 50% ethanol extract of peel followed by ethyl acetate (EA) fractionation (LDSK50-EA) and its aqueous phase (LDSK50-H2O). Therefore, these two active fractions were selected for further studies on their antioxidative activity against DNA damage by hydrogen peroxide (H2O2) in human TK6 cells using comet assay. The comet results revealed DNA-protective activity of both LDSK50-EA and LDSK50-H2O fractions when TK6 human lymphoblast cells were pre-treated at 25, 50, 100, and 200 μg/mL for 24 h prior to H2O2 exposure. The phytochemical analysis illustrated the presence of phenolic substances, mainly scopoletin, rutin, and chlorogenic acid, in these two active fractions. This study generates new information on the biological activity of L. domesticum. It will promote and strengthen the utilization of L. domesticum by-products.
The hydrodistilled essential oil from the rhizome of Zingiber ottensii collected in Phetchaburi province, Thailand was analyzed by GC and GC/MS. Twenty-eight constituents were identified of which zerumbone (40.1%), terpinen-4-ol (11.2%), pcymene (6.9%), sabinene (6.5%) and humulene (5.6%) were the major components. Cytotoxic activity using brine shrimp lethality test showed moderate toxicity (LC 50 = 65.5 µg/ml).
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