D carvone

D-carvone (> 96% purity) (Figure 1) was obtained at Sigma Aldrich (USA). Fetal bovine serum (FBS), Dulbecco's modified eagle medium (DMEM), penicillin (100 units/ml), streptomycin (100 g/ml), trypsin-EDTA, phosphate
buffered saline (PBS), 2', 7'-dichlorofluorescin diacetate (DCFH-DA), acridine orange (AO)/ethidium bromide (EB), 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), rhodamine-123 (Rh-123) and propidium iodide (PI) staining were obtained from
HiMedia (USA).

In this study, facial expressions were elicited by odor samples. The participants evaluated the samples for pleasantness, intensity, and familiarity on visual analogue scales (10‐cm line scales printed on paper). After scaling, the participants described the quality of the odor with their own words (they were asked to write 1–5 descriptive words/sample). The samples were: sea buckthorn juice (20% in tap water), rapeseed oil with garlic (100%), balsamic vinegar (100%), and l‐carvone, d‐carvone, and beta‐ionone (10%), all diluted with propylene glycol (>99.5%; Sigma Aldrich). Selection of the flavoring ingredients and odorants was based on their ability to produce an adequate odor. Water was provided for the participants to neutralize the sense of smell before sniffing the sample. The order of the samples was randomized but it was kept same for all evaluators, because in this study our focus was on the experiences of the assessors, not on the properties of the samples. Self‐reports were requested after evaluation of each sample.

The Nigella sativa seeds were purchased from a retail store in Adrar, Algeria, during the harvesting season in September 2012. The whole seeds sold in a gunny were packed in a vacuumed plastic bag and transported to Malaysia immediately after being purchased in December 2012. They were then stored in the chiller at 4°C after being identified by Dr. Shamsul Khamis, the botanist from the Institute of Bioscience (IBS), Universiti Putra Malaysia (UPM) under specimen voucher number SK 2518/14. Standard compounds D-carvone, thymoquinone, and carvacrol were purchased from Sigma/Aldrich (St. Louis, MO, USA). Longifolene was purchased from ChromaDex (Irvine, CA).