Study on Chemical Composition of Nauclea Officinalis Leaves

Study the effect of blending hydrophilic agent and water and oil repellent agent on cotton fabric property of antifouling and easy decontaminating. The study shows that blending could make the fabric have property of antifouling and easy decontaminating.

Materials for thin-layer chromatography: silica gel G/60H/GF254 from Qingdao Haiyang Chemical Co., Ltd; Gel: Sephadex LH-20 from Amersham Biosciences of Sweden.All reagents here are technical pure and used after rerun. 1 H NMR and 13 C NMR are measured respectively at 400.13 MHz and 100.6 MHz on Bruker AM-400.0NMR spectrometer with TMS as internal standard.ZF-6 triple-purpose UV analyzer is provided by Jiapeng Tech.Co., Ltd. in Shanghai.
Nauclea officinalis leave is provided by Nauclea Officinalis Farm of Jinguang Pharmaceutical Group in Hainan.The sample is proved to be Nauclea officinalis Merr.Chun by Dr. Shiming Deng from the Oceanography College of Hainan University.The voucher specimens are saved in the Oceanography College of Hainan University.

Extraction and separation
Pick up fresh Nauclea officinalis leaves, dry in the shade, coarsely grind, and percolate by 95% ethanol for one week, then concentrate by pressure reduction to obtain 1.5 kg extractum of Nauclea officinalis leaves.The extractum is in turn extracted with petroleum ether (60-90 ), chloroform and ethyl acetate.Extract liquors are respectively concentrated by pressure reduction to obtain 300 g petroleum ether extract, 85 g chloroform extract and 85 g ethyl acetate extract, and solvents therefrom are recycled.The left water collections should pass through macroporous adsorptive resin.300 g petroleum ether extract is combined with about 7 times its weight of silica gel of 200~300 mesh, dryly fill the column and dryly load the sample, separate by gradient elution with petroleum ether/ ethyl acetate (9:1) -ethyl acetate/methanol (1:1) as eluent.Draw small dots on the origin line of the thin layer chromatography (TLC) plate.3 bands are finally identified as the plate develops.The first band is dryly loaded and separated by gradient elution with petroleum ether / dichloromethane [1:(0~1)] as eluent to get compound 1 (20 mg) and compound 4 (21 mg); the second band is dryly loaded after separation with Sephadex LH-20, and eluted with petroleum ether / dichloromethane to get compound 3 (200 mg); the third band is dryly loaded after separation with Sephadex LH-20, and eluted with dichloromethane / ethyl acetate to get compound 2 (15 mg) and compound 5 (100 mg).The structures of compound 1~5 are shown in figure 1.  Above-mentioned data are in accordance with the reference-reported spectrum data of -sitosterol palmitate (Dong, Xue, 2008, p. 63-66;Huang, Ping, 2008, p. 271-274).Therefore, it can be concluded that the compound 1 is -sitosterol palmitate.

Compound 2
Appearance: Colorless oily matter; non-fluorescence at 254 nm under UV lamp after developing on TLC; grey in 10% sulfuric acid-ethanol solution.

Compound 3
Appearance: White acicular crystal (chloroform); non-fluorescence at 254 nm under UV lamp after developing on TLC; red in 10% sulfuric acid-ethanol solution.
Above-mentioned data are in accordance with the reference-reported spectrum data of -sitosterol (Liu, Zhiping, 2007, p. 140-142).Therefore, it can be concluded that the compound 3 is -sitosterol.

Compound 5
Appearance: Yellow oily matter; from red to purple in 10% sulfuric acid-ethanol solution.

Discussion
Reports on the chemical composition of Nauclea officinalis have been mainly about its bark.However, this paper preliminarily studies the chemical composition of Nauclea officinalis leaves, especially its low polar parts.The separated main products are steroid.There have been abundant reports (Jie, Fei, 2006) on Nauclea officinalis barks which demonstrate that the main constituents of Nauclea officinalis are alkaloid and triterpene.Xuan (2005) reported that the anti-bacterial component in Nauclea officinalis is alkaloid.However, this study on the low polar part of ethanol extract from Nauclea officinalis leaves indicates no alkaloid in them.Therefore, the issues that if there is great difference in chemical composition between leave and bark of Nauclea officinalis, especially if there is the same alkaloid in leave as that in bark, and if the separated compounds in this study have the same anti-bacterial activity should be addressed in the future study.