Preparation of potential antioxidant extracts with less process for storing in a long period is preferable. N. lappaceum rind, well known as a promising source of phenolic antioxidants agricultural residue, was employed to prepare crude extracts by different solvents. The phenolic content, flavonoid content, antioxidant, and anti-tyrosinase activities of the extracts were evaluated. The stability of the potential extract was then assessed for phenolic content and antioxidant activity under various storage conditions. The extractive yields of crude phenolic extract ranged from 16.61 to 28.78%. The ethanolic extract of N. lappaceum rind exhibited potential antioxidant activities and contained a high amount of phenolics and flavonoid contents. The extract remained with a high amount of the phenolic content (up to 88.79%) and retained its antioxidant property under various temperatures (4, 25, and 45 °C) after the first week of the storage period. The results suggest that phenolic content and antioxidant activity of N. lappaceum rind extract, as a nutraceutical or anti-aging ingredients in cosmetics, could be stored at a temperature from 4 °C to 45 °C with or without oxygen exposure at least for 16 weeks.

Cassava (Manihot esculenta (L.) Crantz) is extensively used as food in tropical and subtropical regions. This study aimed to evaluate the biological properties of various parts of cassava. The crude phenolic extracts and polysaccharide fractions of two cassava cultivars (Huaybong 60 and Rayong 72) were determined for the total phenolic and carbohydrate contents as well as biological activities, including antioxidant and tyrosinase inhibition properties. Various parts of cassava were successively extracted by using nhexane, ethyl acetate, and ethanol, respectively, through Soxhlet extraction. Water-soluble and insoluble polysaccharides were extracted with aqueous and aqueous alkaline extraction, respectively. The extraction solvents influenced the extractive yield of crude extracts from various parts of cassava (P < 0.05). The cassava peel (Rayong 72) ethanolic extract was the highest extractive yield (11.97%), while the highest extractive yield of polysaccharides was insoluble polysaccharides from cassava stem (Rayong 72) (9.19%). Cassava leaves extracts contained higher phenolic content (39.54 to 83.98 mg GAE/g extract) and flavonoid contents (110.38 to 287.78 mg QE/g extract). The total carbohydrate content in the root extracts was higher than in other parts. Cassava leaves extracts provide high potential antioxidant activities based on three assays: ferric reducing capacity (507.86 to 966.00 mg TE/g extract), DPPH radical scavenging activity (54.64 to 107.65 mg TE/g extract), and the scavenging activity of ABTS cation radical (478.37 to 989.49 mg TE/g extract). Most of the cassava crude extracts slightly inhibited tyrosinase enzyme activity. In contrast, cassava polysaccharide enhanced tyrosinase activity. The overall results proved that ethanolic extracts of cassava leaves could be considered as an alternative antioxidant active ingredient in food and cosmetics due to their antioxidant activities, whereas polysaccharide fractions, as a tyrosinase-promoting agent, could possibly be applied as a mechanism for preventing hair greying. These findings indicate feasible utilization of cassava for value-added products.

Callisia fragrans (Lindl.) Woodson has been reported to possess several biological activities; however, its potential for skin-related applications remains limited. This study aimed to evaluate C. fragrans leaf extracts prepared using different extraction solvents for their potential for skin-related applications. The extracts were comparatively evaluated for extraction yield, total phenolic and flavonoid contents, and antioxidant activities. The selected 50% (v/v) ethanolic and propylene glycol extracts were further evaluated for cytocompatibility and biological activities in human dermal fibroblasts (HDFs) and RAW 264.7 macrophages. The 50% (v/v) ethanolic extract exhibited the most favorable overall antioxidant profile among the dried extracts. Both selected extracts were cytocompatible at the tested concentrations. The 50% (v/v) ethanolic extract increased HDF cellular metabolic activity to 2.57-fold and markedly reduced UV-induced intracellular ROS production in HDFs and RAW 264.7 macrophages. It also exhibited greater inhibition of LPS-induced nitric oxide production than the propylene glycol extract. However, neither extract enhanced hydroxyproline accumulation under the present experimental conditions. Overall, the 50% (v/v) ethanolic extract exhibited greater biological responses than the propylene glycol extract, particularly in HDF cellular metabolic activity and the inhibition of intracellular ROS and nitric oxide production. These findings suggest that the 50% (v/v) ethanolic extract of C. fragrans leaves has potential for further development as a natural cosmetic ingredient for skin-related applications.