The constituents of essential oil in leaves of Karaj accession of Trigonella foenum graecum

Nutritional value, phytochemical composition, and antioxidant potential of Iranian fenugreeks for food applications

Fenugreeks (Trigonella L. spp.), are well-known herbs belonging to the family Fabaceae, whose fresh and dried leaves have nutritional and medicinal value. In the present study, the content of phytochemical traits (essential oil, diosgenin, trigonelline, total phenol, total flavonoid, total saponins, and total tannins), bitterness value, pigments (chlorophyll, carotenoid, β-carotene, and anthocyanin), vitamins (group B vitamins and ascorbic acid), minerals, and antioxidant activity of thirty cultivated populations belonging to ten Trigonella species were evaluated. The species and populations were significantly different in all studied parameters. A significant positive and negative correlation (p < 0.05) was also observed between the studied parameters. In total, T. teheranica, T. elliptica, and T. foenum-graecum were distinguished as superior species. The results showed that fenugreeks leaves can be considered as a valuable source of food and phytochemical compounds. The obtained data can be help to expand the inventory of wild and cultivated Trigonella species for further exploitation of rich chemotypes in the new foods and specific applications.

Multivariate analysis of seed chemical diversity among wild fenugreek (Trigonella monantha C. A. Mey.) ecotypes

BACKGROUND

Wild fenugreek (Trigonella monantha), a multi-purpose annual plant, has traditionally been used as a food, forage, and medicinal plant. However, the knowledge of the diversity of its chemical characteristics is limited. In this study, 40 wild fenugreek ecotypes collected from their natural habitats in Iran and grown together in field conditions, were analyzed for their seed chemical properties.

RESULTS

The ecotypes were cultivated in a randomized complete block design (RCBD) with three replications. The results of ANOVA revealed a significant difference among the ecotypes for all measured characters (P < 0.01). The results showed a high level of diversity among the ecotypes based on the measured characters, including antioxidant activity (48.19 to 86.85%), phenol (0.82 to 1.51 mg gallic acid per g dry weight), flavonoid (1.07 to 3.11 mg quercetin per g dry weight), trigonelline (0.02 to 0.08 mmol/l), 4-hydroxyisoleucine (0.197 to 0.906 mg/g), sucrose (0.13 to 3.77 mM), glucose (1.07 to 12.1 mM), and fructose (13.3 to 45.5 mM). The cluster analysis divided the ecotypes into four groups and the PCA analysis showed that the three first components explained 73% of the total variance among the ecotypes. Also, heat map correlation revealed that many positive and negative correlations were observed among the measured characters. The results did not show a relationship between the amounts of compounds and the place of sample collection.

CONCLUSIONS

The present study suggests considerable diversity in the seed chemical compositions of the wild fenugreek ecotypes. Therefore, many ecotypes could be useful for medicinal purposes, as well as for human nutrition.

Comparative study of the chemical composition of Trigonella foenum-graecum L. essential oil

Fenugreek is a well-known aromatic plant. Its leaves and seeds are commonly used for their many health benefits and the species is cultivated worldwide. For the first time, essential oils (EOs) from seeds of the Bulgarian and Indian populations were obtained by secondary distillation of hydrolat to extract the residual essential oil therein. They were analyzed by gas chromatography-mass spectrometry and the chemical composition of the two samples was compared. Thirty-six compounds were identified and although the results showed some differences in the component composition of the two essential oils, the major constituents identified in both oils were cubenol, γ-n-amylbutyrolactone and palmitic acid. Moreover, oxygenated sesquiterpenes were the predominant fraction in Bulgarian and Indian seeds oils. Information is limited regarding menthol and γ-n-amylbutyrolactone, which were found in the present study in both oils. The performed analysis confirmed the presence of phytol in fenugreek seeds regardless of the extraction method of the essential oil.