GC–MS profiling and in silico prediction of MAPK receptor activation by fatty acids of watercress oil for hair growth marketed in Saudi Arabia

Abstract

Watercress oil (WCO) is the seed oil of Nasturtium officinale, Brassicaceae family. WCO is a cosmetic for hair growth approved by the Saudi Food and Drug Authority (SFDA). The study aimed to analyze by GC–MS, the phytochemical profile and the safety of WCO as a cosmetic according to SFDA, validates the traditional method of applying hot oil mixtures to the scalp, and also reports the pH, UV absorption, and in-silico binding mechanism of fatty acids for hair growth. The absorption of UV-B light (284.50 nm and 290.60 nm) by WCO suggests that it acts as a sunscreen for the scalp. The pH of the marketed WCO, 5.53 ± 0.02, shall not damage the scalp and hair. The GC–MS analysis confirmed fatty acids as the principal constituents (65.65%) of WCO composed of monounsaturated fatty acids (MUFAs): cis-11-Octadecenoic acid (17.14%), cis-9-Octadecenoic acid (17.11%), cis-13-Eicosenoic acid (11.13%), cis-11-Eicosenoic acid (3.48%), and cis-13-Docosenoic acid (1.64%); saturated fatty acid: n-Hexadecanoic acid (12.89%); saturated fatty alcohol: Docosanol (2.26%). The GC–MS results also confirmed the absence of colorants, toxic solvents, and therapeutic substances in WCO, a cosmetic requirement, according to SFDA. The densities of mixtures of WCO + Coconut oil was 0.801 ± 0.03 mg/mL, and WCO + Olive oil was 0.885 ± 0.01 mg/mL; the kinematic viscosities of WCO + Coconut oil was 21.5 ± 0.0 mm2/s, and WCO + Olive oil was 28.6 ± 0.1 mm2/s at 40℃, which was lesser than the mixtures at 27℃. The decrease in density and viscosity of hot oil mixtures can improve the penetration of oil into the hair filament, which substantiated the traditional application method. In-silico, molecular docking results revealed that all the fatty acid constituents except Docosanol contributed to the hair growth promotion effect by activating MAPK1, MAPK3, and MAPKp38 receptors. This work is the first report on WCO to establish the phytochemical profile to confirm SFDA standard by GC–MS and its in-silico efficiency of activation of MAPK receptors for hair growth.