<![CDATA[Combined extracts of black cumin (Nigella sativa L.) seeds and soursop (Annona muricata L.) or celery (Apium graveolens L.) leaves showed antioxidant and pharmacological activities, with phenolic and flavonoid phytochemicals as potential antioxidants. This study investigated the bioactive compounds, phytochemical contents, proximate analysis, and residual ethanol solvent contents of a black cumin seed extract, as well as its combination with soursop or celery leaf extracts. The ethanol extracts were prepared by maceration and analyzed by GC-MS to identify bioactive compounds and residual ethanol. The total polyphenol and flavonoid contents were measured using a UV-Vis spectrophotometer. A proximate assay was used to determine crude protein, fat, and fiber contents. Microbial contamination and heavy metal contamination (Pb, Cd, and Ag) were also assessed. The extracts were free from residual ethanol and contained several pharmaceutically active compounds, including thymoquinone, stigmasterol, and gamma-sitosterol. All extracts contained flavonoids and phenolics, with total flavonoid contents ranging from 1.5–16.16 mg quercetin equivalents/g and total phenolic contents ranging from 3.1–56.6 mg gallic acid equivalents/g. The crude protein content ranged from 4.61–13.37 %, while the crude fat ranged from 3.58–22.42% and the crude fiber ranged from 0.825–2.30%. All extracts except the soursop leaf extracts met microbial and heavy metal safety standards, suggesting their potential for further development as standardized herbal products but with concerns regarding handling, packing, and storage.]]>
