Characterization of extracted phenolics from black cumin (Nigella sativa linn), coriander seed (Coriandrum sativum L.), and fenugreek seed (Trigonella foenum-graecum)

Abstract

The current project was planned for the extraction and characterization of the bioactive moieties from coriander seed (CS), black cumin seed (BCS), and fenugreek seed (FS) with special reference to their synergistic effect. Purposely, the solvent extraction method was applied by using the water and aqueous methanol (70:30 v/v) at constant temperature (40°C) for 7 h. For the estimation of antioxidant profile of resultant extracts, the indices such as total phenolic content (TPC), total flavonoid content (TFC), DPPH (1,1-diphenyl-2-picrylhydrazyl), β-carotene bleaching assay, FRAP (ferric reducing antioxidant power), and ABTS (2,2′-azino-bis,3-ethylbenzothiazoline-6-sulfonic acid) assay were adapted. Moreover, high performance liquid chromatography (HPLC) characterization of the extracts was also carried out for their active ingredients estimation. The results indicated that the combination of spices in some treatments exhibited more antioxidant activity as compared to their single one. The maximum TPC, TFC, DPPH, β-carotene bleaching assay, FRAP, and ABTS assay were exhibited by methanolic extract of T2 (BCS) as 292.5 ± 9.14 (mgGAE/100 g), 188.8 ± 5.69 (mgQE/100 g), 46.3 ± 0.32 (IC50 μg/ml), 76.96 ± 0.81 (%), 5.53 ± 0.08 (mg/TEg), and 67.18 ± 0.82 (μmolTE/g), respectively, followed by T4 (combination of CS and BCS) as 290.5 ± 8.54 (mgGAE/100 g), 184.2 ± 5.88 (mgQE/100 g), 48.2 ± 0.48 (IC50 μg/ml), 75.62 ± 0.87 (%), 5.49 ± 0.04 (mg/TEg), and 64.56 ± 0.46 (μmolTE/g) values for respective parameters, whilst least was observed in T6 (combination of BCS and FS) of respective antioxidant indices as 287.2 ± 9.57 (mgGAE/100 g), 175.9 ± 5.79 (mgQE/100 g), 50.7 ± 0.96 (IC50 μg/ml), 73.24 ± 0.59 (%), 5.40 ± 0.09 (mg/TEg), and 61.96 ± 0.58 (μmolTE/g). Moreover, HPLC characterization conforms to the presence of thymoquinone, diosgenin, and phenolic acids, including (chlorogenic acid, caffeic acid, and kaempferol) in BCS, FS, and CS, respectively. Conclusively, spices extraction was dependent upon the type of solvent and showed promising antioxidant potential not only alone but also in their combinations thus can be utilized for mitigating the oxidative-stress-related maladies.

Keywords

• black cumin seed (bcs)
• coriander seeds (cs)
• fenugreek seed (fs)
• antioxidant indices