A new flavonoid isolated from Lotus aegaeus (Gris.) Boiss.

The genus Lotus (Fabaceae) is represented in the Turkish Flora by 20 species [1]. These species can fix nitrogen through the root nodules so they can use as fodder, human food or green manure [2]. Lotus aegaeus (Gris.) Boiss. is known as “devre otu, nohudak, yonca ” in Central Anatolia and used as animal forage and antimicrobial agent for treatment the animal injuries. Ethnobotanical studies indicate that it's poisonous and harmful to animals if it is consumed before the vernal equinox [2]. Proanthocyanidins, cyanogenic glycosides, flavonoids, sterols and triterpenes were isolated from these species so far [3]. In our previous studies, phytochemical content of L. aegaeus (Gris.) Boiss. was investigated for the first time and 7 compounds of the n-butanol extract of aerial parts were determined as quercetin-3-O-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside, quercetin-3-O-β-D-galactopyranoside-7-O-α-L-rhamnopyranoside, kaempferol-3-O-β-xylopyranosyl-(1→2)-α–L-rhamnopyranosyl-7-O-α–L-rhamnopyranoside, kaempferol-3-O-β-D-galactopyranosyl-7-O-α-L-rhamnopyranoside, saponins: wistariasaponin C and D and a cyanogenic glucoside: linamarin, based on literature data. Our following liquid chromatography studies resulted as yielded 2 more flavonoids and their structures identified as kaempferol 3-O-(5''-acetyl) apiofuranoside 7-O-rhamnopyranoside and a new compound for the nature, kaempferol 3-O-(3'',5''-diacetyl) apiofuranoside 7-O-rhamnopyranoside by using spectroscopic (1D-2D NMR and MS) methods. Our biological activity studies are contiuoning on these compounds.

[1] Heyn CC. Lotus L. in: Davis PH, editor. Flora of Turkey and the East Aegean Islands. Edinburgh,: University Press; 1970, 3: 518 – 531.

[2] Kargıoğlu M, Cenkci S, Serteser A, Konuk M, Vural G. Human Ecology 2010; 38: 429 – 450.

[3] Gruber M, Skadhauge B, Yu M, Muir A, Richards K. Can J Plant Sci 2008; 88: 121 – 132.