Flavonoids from Pimpinella kotschyana

The genus Pimpinella is represented by 23 species in the flora of Turkey, 5 of them are endemic. Pimpinella species have carminative, expectorant, sedative, antidepressant, antiseptic, insecticidal, antiviral, antispasmodic, nematocidal, mutagenic, analgesic, antifungal, antibacterial, diuretic, estrogenic, antimalarial, pectoral, stimulant. The essential oils from the fruits of some Pimpinella species are also valuable in perfumery and in medicine. Earlier investigations of Pimpinella resulted in the isolation of terpenoids, lipids, alkaloids, coumarins, flavonoids and phenylpropanoids. Pimpinella are reported to contain iridoids, diterpenoids, essential oils, ketosteroids and flavonoids. In this study, dried and powdered flowering stems of Pimpinella kotschyana were extracted with MeOH. Methanolic extract was dissolved in H₂O and partitioned with CH₂Cl₂ followed by n-BuOH. Firstly, the n-BuOH phase (57g) was fractionated on a silica gel column. The subfractions were further chromatographed over silica gel, reversed phase silica gel and Sephadex LH-20 to give two new acylated flavonol glycosides together with four known flavonol glycosides: Kaempherol 3-O-α -L-2″- E-feruloyl, 3″- E-p-coumaroyl) rhamnopyranoside, kaempherol 3-O-α-L-(3″-E-feruloyl) rhamnopyranoside, kaempherol 3-O-rutinoside, quercetin-3-O-α-L-rhamnopyranoside, quercetin-3-O-rutinoside, isorhamnetin 3-O-α-L- rhamnopyranoside. The structure elucidation of the isolated compounds were done by spectroscopic methods [1D and 2D NMR spectra and MS data interpretation] and by comparison of their physical and spectroscopical data with literature values. This is the first report describing the isolation of flavonoids from the aerial parts of Pimpinella kotschyana.