No abstract

No abstract

The heartwood extract of Artocarpus lakoocha Roxb. was evaluated for the in vitro tyrosinase inhibitory activity and the in vivo melanin-reducing efficacy in human volunteers. The IC(50) of the extract and oxyresveratrol, its major active ingredient, against mushroom tyrosinase was determined to be 0.76 and 0.83 mug mL(-1), respectively. The extract dissolved in propylene glycol was subsequently tested in female volunteers using a parallel clinical trial with self-control (n = 20 per group). The first group received the 0.25% w/v A. lakoocha solution as the test solution, whereas the second and the third group, respectively, received 0.25% licorice extract and 3% kojic acid as the reference solutions in the same solvent. The subjects in each group twice daily applied the test (or reference) solution in one of her upper arm, whereas the remaining arm was treated with only propylene glycol (self-control) for 12 weeks. The melanin content of each application site was measured using Mexameter every week and calculated as % reduction in melanin content relative to the initial melanin value (% whitening). The value of % whitening was then compared between the product-treated and the propylene glycol-treated arms within the same subject using paired t-test (alpha = 0.05). The A. lakoocha extract was the most effective agent, giving the shortest onset of significant whitening effect after only 4 weeks of application (P < 0.05), followed by 3% kojic acid (6 weeks) and 0.25% licorice extract (10 weeks). The effect also increased with time with maximum whitening observed at week 12 for A. lakoocha extract. When the extract was formulated as an oil-in-water emulsion, its whitening efficacy was further enhanced. Daily application of 0.1% w/w A. lakoocha lotion to the upper arms (n = 25) and cheeks (n = 15) of volunteers produced significant whitening over the lotion base after 2 and 3 weeks, respectively (P < 0.05). Thus, the preliminary study suggested that the heartwood extract of A. lakoocha may have a promising potential for use as an effective and economical skin-whitening agent.

Avicennia marina (AM) exhibits various biological activities and has been traditionally used in Egypt to cure skin diseases. In this study, the methanolic heartwood extract of AM was evaluated for inhibitory activity against 5α-reductase (5α-R) [E.C.1.3.99.5], the enzyme responsible for the over-production of 5α-dihydrotestosterone (5α-DHT) causing androgenic alopecia (AGA). An AGA-relevant cell-based assay was developed using human hair dermal papilla cells (HHDPCs), the main regulator of hair growth and the only cells within the hair follicle that are the direct site of 5α-DHT action, combined with a non-radioactive thin layer chromatography (TLC) detection technique. The results revealed that AM is a potent 5α-R type 1 (5α-R1) inhibitor, reducing the 5α-DHT production by 52% at the final concentration of 10 µg/mL. Activity-guided fractionation has led to the identification of avicequinone C, a furanonaphthaquinone, as a 5α-R1 inhibitor with an IC 50 of 9.94 ± 0.33 µg/mL or 38.8 ± 1.29 µM. This paper is the first to report anti-androgenic activity through 5α-R1 inhibition of AM and avicequinone C.

BackgroundAndrogenic alopecia (AGA) is a major type of human scalp hair loss, which is caused by two androgens: testosterone (T) and 5α-dihydrotestosterone (5α-DHT). Both androgens bind to the androgen receptor (AR) and induce androgen-sensitive genes within the human hair dermal papilla cells (HHDPCs), but 5α-DHT exhibits much higher binding affinity and potency than T does in inducing the involved androgen-sensitive genes. Changes in the induction of androgen-sensitive genes during AGA are caused by the over-production of 5α-DHT by the 5α-reductase (5α-R) enzyme; therefore, one possible method to treat AGA is to inhibit this enzymatic reaction.MethodsRT-PCR was used to identify the presence of the 5α-R and AR within HHDPCs. A newly developed AGA-relevant HHDPC-based assay combined with non-radioactive thin layer chromatography (TLC) detection was used for screening crude plant extracts for the identification of new 5α-R inhibitors.ResultsHHDPCs expressed both 5α-R type 1 isoform of the enzyme (5α-R1) and AR in all of the passages used in this study. Among the thirty tested extracts, Avicennia marina (AM) displayed the highest inhibitory activity at the final concentration of 10 μg/ml, as the production of 5α-DHT decreased by 52 % (IC50 = 9.21 ± 0.38 μg/ml).Conclusions Avicennia marina (AM) was identified as a potential candidate for the treatment of AGA based on its 5α-R1-inhibitory activity.