11 th NAPRECA Symposium Book of Proceedings, Antananarivo, Madagascar Pages 187-192 Shode et al. 187 Extractives from Heteropyxis natalensis F O Shode a, * , R T Oyede a , J K Adesanwo b , and H Baijnath c a School of Chemistry & c School of Conservation & Biological Sciences-Westville Campus, University of KwaZulu-Natal, P/Bag X54001, Durban 4000, South Africa. b Chemical Sciences Department, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria. Abstract (2E)-2-[(2E)-1-hydroxy-3-phenylprop-2-en-1-ylidene]-5-methoxy-6,6-dimethylcyclohex-4- ene-1,3-dione (ceroptin), and two other flavonoids have been isolated from the leaf extract of Heteropyxis natalensis. Their structures were determined using both 1D- and 2D-NMR as well as X-ray diffraction studies. Keywords: Heteropyxis natalensis; Heteropyxidaceace; ceroptin, flavonoids, x-ray analysis Introduction The family Heteropyxidaceace is a small family with only three species in southern Africa namely Heteropyxis canescens, H. dehniae, and H. natalensis, commonly known as Lavender tree or Laventelboom, ranges from Zimbabwe through the Northern Province, Mpumalanga and KwaZulu-Natal of South Africa. It is a slender, upright tree which grows to about 10 meters high. 1 It is recorded as a Zulu medicinal plant used as medicinal tea. Its bark is used to treat impotence and as an aphrodisiac. 2 Previously, several investigators have examined the essential oils from the leaves of H. natalensis. 3 In our on-going search for bioactive natural products as leads for new ethnopharmaceuticals, H. natalensis was subjected to phytochemical examination. Our preliminary results are reported herein. Re sults a nd Disc ussio n The chromatographic fractionation of the hexane, dichloromethane, and ethyl acetate extracts of the leaves of H. natalensis afforded compounds A, B, C, and D as major extractives as well as two minor constituents. The 13 C NMR spectrum of compound A (yellow crystalline compound mp. 136  )(Table 1) shows 18 signals including two signals at δ CH 144.63 and 123.38 characteristic of the β and α carbons of a chalcone structure 4 , seven sp 2 CH (δ 30.52, 128.87, 130.52, 123.38, 95.58, and 56.55 ), one sp 2 quaternary carbon (δ180.08), four sp 3 carbons ( δ56.55, 1 x OCH 3 , δ 49.27, 1 x C(CH 3 ) 2 , δ24.67, 2 x CH 3 ), and three carbonyl groups ( δ197.60, 190.93, and 187.78). The 1 H NMR spectrum (Table 1) showed two signals corresponding to five aromatic protons at δ7.65 (2 x ArH) and δ 7.36 (3 x ArH), two doublets at δ8.30 (1 x H, 15.9 Hz) and δ 7.89 (1 x H, 15.8 Hz) attributable to trans olefinic protons, one downfield singlet at δ5.48, a singlet at δ3.81 (1 x OCH 3 ), a singlet at δ 3.74 (1 x olefinic proton), and a singlet at δ1.38 (2 x CH 3 ). These data are in agreement with a chalcone structure in which ring A is non-aromatic with three oxygen functions and unsubstituted ring B. The molecular formula ,C 18 H 18 O 4 , which was obtained by HREIMS m/z [M+, 100] 298.1234 (calc. 298.1205 for C 18 H 18 O 4 ) led us to propose structure 1 for compound A.