Physicochemical properties and wound healing effect of black cumin seeds oil from Saudi Arabia

Abstract

Black cumin (add scientific name) planted in Qassim, Saudi Arabia was studied. The seeds oil and essential oil were extracted using cold press and Soxhlet extraction methods. The Soxhlet method applying solvents with varied polarity were used to study the effect of solvent polarity on free fatty acids and triacylglycerol's (TAGs) components of the extracted oils. Folin-Ciocalteu, 2, 2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays were used to evaluate the antioxidant activity of each BCSO sample. The extracted oils were tested in vitro as a topical treatment for healing wound in rats. HPLC profile showed that BCSO samples were rich in unsaturated triacylglycerols, mostly as 1,2,3-trilinoleylglycerol. GC-FID analysis showed that saturated and unsaturated fatty acids were both present. BCSO from cold press extractor contained a high concentration of linoleic acid (58.0%), oleic acid (21.9%) and palmitic acid (10.1%). These fatty acids and their TAGs were precursors for critical components in wound repair. GC-MS profile revealed the presence of two important bioactive compounds; thymoquinone and thymol that are essential for healing wounds. Moreover, the Folin-Ciocalteu assay showed that BCSO from aqueous methanol extractor showed a high level of total phenolic compounds (239 mg GAE/g). Furthermore, DPPH radical scavenging activity of seed oils evaluated in terms of their inhabitation% indicate a variation between (34-59 %). Ferric reducing antioxidant power activity for BCSO THF extractor was 13326 mmol Fe2+/100g dry weight. Wound healing in vitro studies showed that 100% recovery was reached after fifteen days of treatment, when using BCSO cold pressing extractor. The period was decreased to ten days of treatment when using mixtures composed of BCSO with Olive oil (1:1), or BCSO with honey (1:1). BCSO ointment showed a promising wound healing effect compared to control samples. This is probably due to the synergetic effect of the detected fatty acids, TAGs and bioactive components. Results of this study may lead to the development of a healing agent for open and diabetic wounds and skin grafting.