Amaç: Primer metabolitler, bitkinin temel yaşamsal işlevlerinde doğrudan etkiliyken, sekonder metabololitler ise doğrudan etkili olmayan, bitkinin hayatta kalması ve bulunduğu ortama uyum sağlaması ile ilgili görevleri olan biyoaktif bileşiklerdir. Fonksiyonel gıdalarda, kozmetik ürünlerde, tarım ve zirai uygulamalarda, aromaterapide, boyalar ve diğer endüstriyel ürünlerde kullanım alanlarının olmasının yanında birçok ilaç ve sağlık ürünü de bitkisel kaynaklı sekonder metabolitlerden elde edilir. Bitkilerin çevresel etkileşimlerine yanıt olarak oluşturdukları bileşikler olan sekonder metabolitler, bitkilerin savunma mekanizmalarında, iletişimde ve çeşitli biyolojik süreçlerde rol oynarlar. Hem bitkilerin kendileri, hem de insanlar açısından faydalı olan bu bileşiklerin biyosentezlerini ve akümülasyonlarını etkileyen faktörlerin araştırılması önemlidir. Sonuç ve Tartışma: Bitki sekonder metabolitlerinin biyosentezi ve akümülasyonu üzerinde etkili olan çeşitli genetik, ontogenik, morfogenetik ve çevresel faktörler incelenmiştir. Diğer tüm faktörler sabit kalsa da sadece bir faktördeki değişiklik bitkilerde sekonder metabolitlerin içeriğini ve miktarını seçici olarak değiştirebilmektedir. Ayrıca, bitki büyümesini ve verimliliğini, bunun sonucunda da sekonder metabolit üretimini artırmak için, metabolomik, proteomik ve transkriptomik gibi yeni yöntemler kullanılarak çeşitli çevresel etkenlerin sinerjistik etkilerini moleküler seviyede anlamak amacıyla daha fazla araştırmaya ihtiyaç vardır.

HIGHLIGHTS The phenolic composition, antioxidant activity and cytotoxic potential of the extracts of C. solstitialis and U. picroides were investigated. Caffeic acid was found as the most abundant phenolic compound in the extracts. Both species showed promising antioxidant activity towards different assays. The highest cytotoxic potential was observed in the extract of C. solstitialis.

In this research, the phenolic composition, antioxidant, antibacterial and cytotoxic activities of the methanolic extracts obtained from Alyssum fulvescens var. fulvescens aerial parts known as Ege kuduzotu in western Turkey, were firstly investigated. The antioxidant activity of the extract was determined by DPPH, metal chelating, phosphomolybdenum, β-carotene/linoleic acid and ferric reducing power assays. Moreover, total phenolic and flavonoid contents in the extract were investigated. The brine shrimp (Artemia salina L.) lethality test was used to investigate for the possible cytotoxic activity of the extract. Microdilution broth method was used to study antibacterial potency of extract against Gram-positive and Gram-negative bacteria. The extract exhibited good biological activities. Total phenolic and flavonoid contents in the extract were significantly correlated with antioxidant potentials. HPLC analysis showed that chlorogenic acid was the major phenolic in extract tested. The results indicated t...

Medicinal plants in the world are natural antioxidant sources as they contain some secondary metabolites such as phenolic acids and flavonoids. Therefore, they are used to prevent or treat many diseases in many parts of the world. However, the use of antioxidants in cancer treatment is still controversial. Accordingly, the phenolic composition and antioxidant potential of the ethanol extracts of Momordica charantia L. (Cucurbitaceae) and Datura stramonium L. (Solanaceae), which are used traditionally in Turkey and have cytotoxic potential on human cancer cells, were investigated. The antioxidant assays (DPPH, metal chelating, phosphomolybdenum, and ferric reducing power) were applied to the ethanol extracts of the fruits of M. charantia and the leaves of D. stramonium. The total phenolic and flavonoid contents were determined. The phenolic compounds contained in ethanolic extracts were identified using HPLC method. Fifteen phenolic compounds were identified in the extracts. Caffeic acid was the major constituent in both extracts. The amount of caffeic acid was detected to be 6282.51 and 15183.36 µg g-1 extract in M. charantia extract and the D. stramonium extracts, respectively. D. stramonium leaf extract showed higher antioxidant activity than M. charantia fruit extract and this activity may be associated with high phenolic compound concentrations. Hence, further studies about screening of bioactive compounds from various part of these plants will be a great importance for obtaining of source of novel natural antioxidants.