Studies On The Chemical Constituents And Quality Evaluation Method Of The Leaves Of Moringa Oleifera

Moringa oleifera Lam,also known as drumstick tree,is widely distributed in east Africa and northern India.Since early 1960 s,M.oleifera has been commercially grown in Taiwan,Hainan,Guangdong,and Yunnan provinces of China.The whole plant of M.oleifera is commonly used as folk medicine,the leaves of which were verified to show hypoglycemic,anti-inflammatory,liver protection,anti-oxidation,and anti-tumor activities.Previous phytochemical investigations on the leaves of M.oleifera revealed that flavonoids,phenols and phenolic glycosides,amino acids,as well as vitamins are the main chemical components.In recent years,there are a lot of health foods made by the rough processed leaves of M.oleifera selling in the market.However,due to the lack of authoritative quality control method of the leaves of M.oleifera,the quality of those marketing products can not be guaranteed.In order to elucidate the characteristic constituents of the leaves of M.oleifera,and provide scientific basis for the quality control of their related products,the following research works were performed:1.Phytochemical investigation on the leaves of M.oleifera led to the isolation of twent y-one compounds.On the basis of extensive spectroscopic analyses,their structures w ere identified as kaempferol(LM-1),isovitexin(LM-2),vitexin(LM-3),astragalin(L M-4),isoquercitrin(LM-5),vicenin-2(LM-6),quercetin 3-O-6''-(3-hydroxyl-3-methylgl utaryl)-?-D-glucopyranoside(LM-7),kaempferol 3-O-?-D-(6''-malonyl)-glucopyranoside(LM-8),quercetin 3-O-?-D-(6''-malonyl)-glucopyranoside(LM-9),benzyl-O-?-D-glucop yranoside(LM-10),4-O-?-D-glucopyranosyl-benzoic acid(LM-11),gallic acid(LM-12),marumoside B(LM-13),5-caffeoylquinic acid(LM-14),3-caffeoylquinic acid(LM-15),4-caffeoylquinic acid(LM-16),L-phenylalanine(LM-17),L-tryptophane(LM-18),(–)-(1S,3S)-1-methyl-1,2,3,4-tetrahydro-?-carboline-3-carboxylic acid(LM-19),(–)-(1R,3S)-1-methyl-1,2,3,4-tetrahydro-?-carboline-3-carboxylic acid(LM-20),and adenosine(LM-21),respectively.Among them,LM-6,LM-19,and LM-20 are isolated from thi s plant for the first time.2.An UPLC fingerprint chromatogram method for the leaves of M.oleifera was establis hed.The method was developed on Agilent Eclipse XDB-C18(3.0 mm × 100 mm,1.8 ?m)column with gradient mobile phase consisting of acetonitrile and 0.01% TFA water at the flow rate of 0.5 m L/min.The UV detection wavelength was 210 nm an d the column temperature was 35 oC.As a result,the UPLC characteristic fingerprint of the leaves of M.oleifera was established and 12 common peaks were found and identified by comparinson with the reference compounds isolated from the same plan t in our current investigation.The reference sample was isoquercitrin(S)and the rela tive retention times were 0.08(No.1,adenosine),0.14(No.2,L-phenylalanine),0.22(No.3,5-caffeoylquinic acid),0.28(No.4,L-tryptophane),0.42(No.5,4-caffeoylqu inic acid),0.65(No.6,vicenin-2),0.94(No.7,vitexin),0.96(No.8,isovitexin),1.00(No.9,isoquercitrin),1.11(No.10,quercetin 3-O-?-D-(6''-malonyl)-glucopyranoside),1.21(No.11,astragalin)and 1.37(No.12,kaempferol 3-O-?-D-(6''-malonyl)-glucopy ranoside),respectively.3.An UPLC method was developed to simultaneously determine the contents of L-phenylalanine,5-caffeoylquinic acid,L-tryptophane,4-caffeoylquinic acid,vicenin-2,isoquercitrin,and astragalin.The analysis method is consistent with that of its characteristic fingerprint.The concentrations of the above seven principal components were determined using the external standard method by analyzing 14 batches samples.The content of L-phenylalanine was ranged from 0.39 to 4.20 mg/g(average 1.76 mg/g),5-caffeoylquinic acid was ranged from 1.22 to 5.46 mg/g(average 3.15 mg/g),L-tryptophane was ranged from 0.29 to 2.46 mg/g(average 1.07 mg/g),4-caffeoylquinic acid was ranged from 0.16 to 2.28 mg/g(average 1.14 mg/g),vicenin-2 was ranged from 0.78 to 4.27 mg/g(average 2.19 mg/g),isoquercitrin was ranged from 0.54 to 3.18 mg/g(average 1.43 mg/g)and astragalin was ranged from 0.22 to 1.64 mg/g(average 0.93 mg/g),respectively.The above results provide the scientific basis for the quality control and the development of quality standards of the leaves of M.oleifera and their related products.