Crude extracts of Alpinia conchigera a species from the Malaysian Ginger (Zingiberaceae) family and its fractions obtained from various extraction methods were assayed for melanogenesis inhibition activity and cell viability. The crude extract obtained from the ethanolic extraction and the super critical fluid extraction did not exhibit significant melanin inhibition activity and was shown to be toxic to the melanocyte cells in comparison to the water extract. The crude aqueous extracts displayed melanin inhibition of 96.38 ± 1.60% and cell viability 109.90 ± 8.32% at a concentration of 500 µg/mL. Bioassay guided fractionation was performed on the water extracts to isolate the active compounds. The actives were identified as trans-cinnamaldehyde and chavicol glucopyranoside with both compound showing potent anti-melanogenesis activity. At 4.9 µg/ml, both trans-cinnamaldehyde and chavicol glucopyranoside gave 85% inhibition of melanin formation in vitro with 77% and 97% cell viability respectively. In comparison, kojic acid, a known skin lightening agent showed 90.0% inhibition at 100 µg/mL. The bioactive composition comprising the extract, active fraction, purified compounds or mixture thereof of Alpinia conchigera may be used for cosmetic and pharmaceutical applications, particularly for the purposes of reducing skin pigmentation.

The increasing demands on anti-oxidant and skin lightening agents in Asia Pacific market have created vast excitement in the cosmetic and pharmaceutical industry to introduce robust and effective, yet safe invention of topical product. The emergence of various herbal-based products stimulates comprehensive study to evaluate the potential of various tropical plants. Seaweed is a marine tropical alga that has been claimed to possess good anti-aging and anti-pigmentation activity. Nonetheless, these claims are not supported by strong scientific evidences. Three species of Malaysian tropical seaweed, Turbinaria sp. (TR), Gracilaria sp. (G) and Padina sp. (PD) were studied for anti-oxidant and skin lightening properties. Crude aqueous extracts of the selected seaweed species (TRA, GA and PDA) were evaluated using ABTS and mushroom tyrosinase assay, for anti-oxidant and skin lightening activity, respectively. Amongst the extracts, TRA showed the most potent anti-oxidant activity. This extract displayed lower IC 50 value of 0.063 ± 0.001 mg/ml, whilst commercial anti-oxidant agent, vitamin C (L-ascorbic acid) demonstrated better IC 50 value at 0.008 mg/ml. In addition, TRA showed good skin lightening activity at 2 mg/ml with 50.11 ± 0.04 % inhibition against tyrosinase enzyme activity. Therefore, this study could underpin the dual inhibitory effect of the selected seaweed species as anti-oxidant and skin lightening agent for topical application. The cellular antioxidant activity (CAA) for quantifying the antioxidant activities will then further evaluate to measure the antioxidant potential of seaweed extracts. The cell based bioassay represents a promising analytical tool for potential biological activity.