;t, 6uflu aem. floe., Vol. LV, November 1978, pp. 1175-1118 Physalolactone : A New Withanolide from Physalis peruviana A. B. RAY and M. SAHAI Department of Medicinal Chemistry,I.M.S., Banaras Hindu University, Varanasi-22100S,India and B.C. DAS Institut de Chimie des Substances Naturelles, Oif-sur-Yvette, France Physalolaetone, a new witbaaolide isolated from the leaves of Physalis peruviana, bas been characterised as (17S, :ZOS, :Z:ZR)·Ck·cbloro-4,B,S,B,l<k,17,:ZO..pentabydroxy-1-oxowitba·:Z,24- dlenollde (I) from chemical and spectral evidences. pHYSALIS peruviana Linn. (Solanaceae) is widely cultivated in India for its edible berries. We already 1 reported the structure determination of physoperuvioe, a biogenetic variant of tropane alkaloids, isolated from its roots. The present paper describes the structure elucidation of a new withanoUde, physalolactonc{I), isolated from the leaves of tho same plant. Chromatographic resolution of the ether-soluble fraction of the alcoholic extract of the leaves of P. peruviana led to tho isolation of a number of steroidal COOStituents, the major one of which was designated as pbysalolactone, C 118H 89 0 8 Cl. HliO, m.p. 227-28°, f<]z; + 29.4° (pyridine). It was recognised to have a 20-bydroxy-1-oxowitha-2,24-dieonolide skeleton from spectral data discussed in the sequel. Mass spectrum of physalolactone, in addition to the twin molecular ion peaks at m/e 538/540, showed important ion peaks at m/e 125 (65%), 152 (base peak) _p). I OH ¢( + g_ Cl I , R "'II H, .fOH II, O ;;·· /·_cp bH o o c• and 169 (50%) due to ions a, band c respectively. While the ions a and bare considered to be diagnostic peaks for a withanolide skeleton ll, ion c suggested the presence of a hydroxyl group at C-20. The IR spectrum of physalolactone showed only one broad carbonyl absorption at 1673 cm- 1 (overlap of both c(, P-unsaturated ketone and lactone 8 } and its UV spectrum showed maximum absorption at 217 om (e, 11,700\, characteristic of the summation spectrum of enonc and c(, P-unsaturated lactone chromophores'· 5 • The PMR spectrum of physalolactone showed five methyl singlets, three of which are attributable to tertiary and two to vinylic methyls (Table 1). Tbe low-field methyl singlet at d, 1.24 for 21-metbyl confirms the presence of a hydroxyl group at C-20. as indicated from mass spectrum. The olefinic protons at C-2 and C-3 appeared as doublet and double doublet, respectively at d, 5.82 and 6.63. -/). + +oH ll .£ IV v Vl VII l17.S