No abstract

Cashmins A (1) and B (2), two new coumarins, have been isolated from the chloroform-soluble subfraction of the methanolic extract of Sorbus cashmiriana Hedl. Both compounds showed potent antioxidant activity in different antioxidant assays.The genus Sorbus (Rosaceae) comprises of 200 species which are commonly grown in Asia, Africa, and South America. Out of these, seven species have so far been identified in Pakistan. One of these is Sorbus cashmiriana Hedl., which is a tree found in Kashmir and the western Himalayas. A tea made from its bark is used to treat nausea. The bark preparation is also used to treat heart diseases. Berries are used to cure scurvy [1][2][3][4][5]. Previously six new triterpenes have been reported by us from this plant [6][7][8]. Its methanolic extract showed significant antioxidant activity. On further fractionation, the major activity was detected in the chloroform-soluble subfraction. This prompted us to carry out bioassay-directed isolation studies on this fraction, resulting in the isolation of two new coumarins named cashmins A (1) and B (2). Both compounds showed potent antioxidant activity in different antioxidant assays.Cashmin A (1) was obtained as a white amorphous solid and gave a violet coloration with FeCl 3 for a phenol. The molecular formula was established as C 22 H 16 O 7 through HR-EI-MS, showing an [M] + peak at m/z 392.0896 (calcd 392.0899). The IR spectrum showed the presence of a hydroxyl group (3360 cm -1 ), an D,E-unsaturated lactone (1700 cm -1 ), and an olefinic bond (1630 cm -1 ). The UV spectrum was characteristic of a coumarin showing absorption maxima at 230, 262, and 322 nm [9]. The 13 C NMR (Table 1) and DEPT spectra of 1 showed 22 carbon signals, including one methyl, ten methines, and eleven quaternary carbons. The most downfield signal at G 162.2 was assigned to the carbonyl carbon of D,E-unsaturated lactone moiety.

Allumines A and B (1 and 2, resp.), two new steroidal alkaloids, and a new cyclopentene derivative, 3, were isolated from the CHCl 3 -soluble fraction of the whole plant of Allium victorialis. Their structures were elucidated by spectroscopic techniques, including 1D-and 2D-NMR spectroscopy.

Alliumonoate, a new cyclopentane derivative, has been isolated from the chloroform-soluble fraction of the ethanolic extract of Allium victorialis, along with β-amyrin acetate, β-sitosterol acetate, 22-cyclohexyl-1-docosanol, β-amyrin, β-sitosterol, and β-sitosterol 3-O-β-D-glucopyranoside, reported for the first time from this species. Their structures were elucidated on the basis of spectral data including mass spectra and 2D NMR experiments.