Antioxidation and Melanogenesis Inhibition of Various Dendrobium tosaense Extracts

Abstract

This study investigated the polyphenol content, antioxidant activity, and inhibition ability of mushroom tyrosinase and melanogenesis of Dendrobium tosaense (DT) extract. Ground DT was extracted using deionized water (W) or 50% ethanol (50E) at room temperature (RT) or 50 °C (50T) for 20 min. The 50T + 50E extract exhibited the highest total phenol content 47.0 ± 4.0 mg gallic acid equivalent/g DT extract, the highest level of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging 66.0 ± 3.0 mg Trolox equivalent/g DT extract, and the highest reducing power 12.00 ± 0.50 mg vitamin C equivalent/g DT extract. The RT + W extract had the highest total flavonoid content 110.0 ± 3.0 mg quercetin equivalent/g DT extract. The RT + 50E extract had the lowest half maximal inhibitory concentration 1.30 ± 0.00 mg/mL for 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging, and the lowest half maximal inhibitory concentration 6.40 ± 0.30 mg/mL for mushroom tyrosinase inhibition activity. DT extracts, especially RT + W and 50T + W, exhibited potent inhibitory effects on melanogenesis of B16/F10 cells. These results demonstrated the application potential of DT extract for skincare.

Effects of Infusion and Storage on Antioxidant Activity and Total Phenolic Content of Black Tea

“…The total phenolic content of the tea sample was determined using the Folin-Denis method devised in previous reports [16][17][18]. Every black tea sample was mixed with 0.8 mL of Folin-Denis reagent for 3 min.…”

Functionality Analysis of Spent Coffee Ground Extracts Obtained by the Hydrothermal Method

“…As mentioned in the previous reports [14][15][16], the present study uniformly mixed 50 μL of 198 μM DPPH ethanol solution and 50 μL of the SCG extract solution; the mixture was allowed to react in darkness for 30 minutes. Optical absorbance at 517 nm was measured using a spectrophotometer; a low optical absorbance reading indicated that the sample had high DPPH free-radical scavenging activity.…”

“…Following previous methods [14][15][16], the present study uniformly mixed 250 μL of 7 mM ABTS with 250 μL of 2.45 mM potassium peroxydisulfate; the mixture was allowed to react at 4°C in darkness for 16 hours.…”

“…Tyrosinase Inhibition Capacity Assay. As per the method used [14,16], the present study first uniformly mixed 20 μL of the SCG extract solution, 40 μL of 3 mM L-Dopa, 10 μL of 200 U tyrosinase, and 130 μL of 67 mM PBS; the mixture was placed in a 37°C water bath for 15 minutes. Optical absorbance at 475 nm was measured; a low optical absorbance reading indicated high tyrosinase inhibition capacity.…”

Efficiency of Skin Whitening Cream Containing Etlingera elatior Flower and Leaf Extracts in Volunteers

“…In the past few decades, research has demonstrated that natural bioactive compounds are increasingly being used in whitening cosmetic formulations. In addition, there are several plant extracts that have been shown to be effective agents to suppress the overproduction of melanin or to regulate melanin synthesis, such as Cassia fistula flowers [31], Asphodelus microcarpus [32], Magnolia officinalis [33], Dendrobium tosaense [34], and Kummerowia striata [35]. The results of the present study indicated that extracts of E. elatior flowers and leaves achieved a decent skin whitening effect on human volunteers; therefore, these extracts act as the active whitening ingredient in FL1 cream.…”