Study On Antifungal And Insecticidal Activities And Chemical Constituents Of The Ethanol Extract Of Berchemiella Wilsonii (Schneid.) Nakai

Berchemiella wilsonii(Schneid.)Nakai is a shrub plant of the Berchemiella genus to family Rhamnaceae,which is mainly distributed in Yunnan and Hubei.As an endemic species of micro-domains in China,B.wilsonii is a national secondary protected plant and is known as the “plant giant panda”.Its closely related genera are Berchemia and Rhamnella,which can be used as traditional Chinese medicine.The extracts or chemical constituents of the two genra have been revealed various pharmacological biological activities,such as anti-oxidation,anti-histamine,anti-tumor,enzyme inhibition,anti-inflammatory and analgesic.However,for the rare species of B.wilsonii,the biological activity research is very limited,and the chemical composition has not been studied.We have noticed that a previous research has screened the antibacterial activity of the crude extract of B.wilsonii,which showed some antimicrobial activities against plant pathogens.Based on above research,the present study carried out broaden investigations of the antibacterial and insecticidal activities of the plant.Moreover,the chemical composition of this plant was investigated by means of thin layer chromatography,column chromatography and high performance liquid chromatography(HPLC)as well as spectral data analysis.The specific research results are as follows:1.The antibacterial activities of the ethanol extract of B.wilsonii and its different extractive phases(petroleum ether,ethyl acetate,n-butanol)were determined.The results showed that the ethanol extract had antibacterial activity against Ralstonia solanacearum,Ervinia carotovora var.carotovora and Pseudomonas syringae pv.lachrymans.At a concentration of 20.0 mg/mL,the bacteriostatic activity of petroleum ether,ethyl acetate and n-butanol extraction phase of the extract was as follows: ethyl acetate > petroleum ether >n-butanol,among which n-butanol extraction phase did not show inhibition effect.Compound(-)-epicatechin(1)has antibacterial effect on the three pathogenic bacteria,and is one of the effective antibacterial components of B.wilsonii.The minimum inhibitory concentration(MIC)for Ralstonia solanacearum and Pseudomonas syringae pv.lachrymans is 75 ug/mL,and the minimum inhibitory concentration(MIC)for Ervinia carotovora var.carotovora 37.5 ug/mL;and the compound 3,4-dihydroxybenzoic acid(7)There is nobacteriostatic effect on the three tested pathogens.2.The insecticidal activity of the ethanol extract of B.wilsonii was investigated.It was revealed that the ethanol extract had insecticidal activity,growth and development inhibitory activity against the infancy larvae of Helicoverpa armigera,and could affect the activity of phenol oxidase in vivo.Under the five concentrations of treatments,the highest corrected mortality was 57.82% at a concentration of 16.0 mg/mL for 4 days,but the mortality did not increase significantly with the increase of the concentration.However,the pupation inhibition of the extract was obvious and concentration-dependent.The pupation rate reduced to 21.67% at the maximum concentration of 32.0 mg/mL.Meanwhile,further test results showed that the insect phenol oxidase activity produced changes.The OD value of phenol oxidase was the lowest and the growth curve was the most gentle under the treatment of 16.0 mg/mL,while the activity of phenol oxidase was the lowest under the treatment of8.0 mg/mL,which were significantly different from that of CK.3.Twelve compounds(1?12)were isolated and identified from the aerial parts o f B.wilsonii for the first time.The compounds were identified as(-)-epicatechin(1),quercetin 3-O-?-L-arabinopyranoside(2),taxifolin(3),vitexin(4),2-hydroxy-4-methoxy-3,6-dimethylbenzoic acid(5),methyl p-hydroxycinnamat(6),3,4-dihydroxy benzoic acid(7),(3S,5R,6R,7E,9S)-3,5,6,9-tetrahydroxy-7-en-megastigmane(8),(6S,9R)-roseoside(9),lupeol(10),erythritol(11),D-(+)-galactose(12).The flavon oids are the main chemical constituents of B.wilsonii;compounds 8 and 9 are two megastigmane derivatives,which were isolated from family Rhamnaceae for the first time.The appearance of megastigmane derivatives in Berchemiella might be important chemotaxonomic marker candidates for species of B.wilsonii.