# Cosmeceutical Potentials of _Equisetum debile_ Roxb. ex Vaucher Extracts
## 4 Discussion
Fatty acids with C12-C16 chains and the presence of double bonds could enhance the inhibitions against 5\(\alpha\)-reductase. \(\beta\)-sitosterol isolated from the hexane fraction of _Dendropanax morhyifera_ showed the capacity to delay hair loss and improve hair density in mice [71]. However, \(\beta\)-sitosterol is less potent than finasteride in the inhibition of 5\(\alpha\)-reductase as demonstrating by the IC\({}_{50}\) of 2.7 \(\mu\)M and 10.12 nM, respectively [72]. For _Equisetum_ plants, the presence of fatty acids and phytosterols could therefore be responsible for the anti-5\(\alpha\)-reductase activity. Moreover, stigmasterol and daucosterol were previously isolated from _E. debile_[55]. Fatty acids and phytosterols are both lipophilic. Therefore, the usages of hexane, dichloromethane, and ethyl acetate may enable the sequestration of fatty acids and phytosterols into the fractions during the solvent-solvent partitioning of crude extract. Taken together, fatty acids and phytosterols may be responsible for HF, DF, and EF exhibiting stronger 5\(\alpha\)-reductase inhibition than CE and MF. Nonetheless, the direct associations between these compounds and the underline mechanisms need to be further characterized in _E. debile_. Some flavonoids, such as fiesetin, genistein, and kaempfer, found in CE by LCMS (Q-TOF) qualification analysis in the present study, were previously reported to inhibit 5\(\alpha\)-reductase activity [73]. These flavonoids may be the responsible compounds in the EF. Currently, finasteride is the only oral drug approved by the US FDA and the European Medicines Agency (EMA) to treat androgenic alopecia. A current recommended and marketed dosage of finasteride is 1 mg per day [2]. Although it is efficacious for hair regrowth, it causes severe side effects such as malignant neoplasms of male breast, sexual disorder, and high-grade prostate cancer. Thus, finasteride is often limited to only short term use. Therefore, exploring advantages of constituents from natural origins could lead to a discovery of novel compounds and functions. This study demonstrates such advantages from _E. debile_. The crude extract of _E. debile_ had an FEA of 0.83 mg/mL, and all semi-purified fractions had FEA values ranging from 0.90 to 1.48 mg/mL. Therefore, a regular intake of _E. debile_ extracts may be a possible natural alternative to chemically synthetic finasteride in preventing and treating androgenic alopecia. Altogether, quercetin and fatty acids could be active compounds of _E. debile_ for skin and hair benefits. Figure 10 shows that all extracts maintained inhibitory activities against tyrosinase and collagenase during a three-month storage period. On the other hand, only DF and MF maintained the anti 5\(\alpha\)-reductase activities, whereas CE, HF, EF, and MR activities were significantly decreased; however, they still had relevant values. Quercetin is a phenolic compound that can undergo many chemical changes by the oxidative process during food processing and storage. The oxygen concentration, pH, temperature, concentration of other antioxidants, as well as the presence of metal ions are known factors affecting the chemical stability of quercetin [74]. Additionally, the fatty acid composition of oils, especially the level of unsaturation, may influence the oxidative stability of the oil [75]. Therefore, further investigation of oxidative stabilities is suggested as the important quality control parameters of both phenolics and fatty acids in _E. debile_ extracts for their potential cosmeceutical applications. This is the first study to report the stability of _E. debile_ extracts by the determination of cosmeceutical potentials of anti-tyrosinase, anti-collagenases, and anti-5\(\alpha\)-reductase activities at three months storage under an accelerated condition at 40 \({}^{\circ}\)C. However, the bioactivity stability should be monitored beyond a three-month period. In the present study, the cytotoxic effects of _E.