Antidiabetic principles of Loranthus micranthus Linn.parasitic on Persea americana

Objective:To explore antidiabetic principles of the Eastern Nigeria mistletoe,Loranlhus micranthus Linn,parasitic on Persea Americana.Methods:The weakly acidic fraction of the aqueous methanol extract of the leaves of Loranlhus micranthus(Linn.) was isolated and tested for its antidiabetic activities.The isolation of the weakly acidic fraction was carried out following established physico-chemical based procedures.Furthermore,alloxan-induced diabetic rats were treated intraperitoneally(ip) with 250 mg/kg and 400 mg/kg of the weakly acidic fraction, glibenclamide 10 mg/kg(positive control) and 2 mg/kg of 3%v/v tween 20(negative control).The sugar levels of the treated and untreated animals were determined by withdrawing the blood at regular intervals and testing them with an automated glucometer.The phytochemical analysis of the acidic fraction was carried out using standard procedures.Chromatographic techniques were employed in the subsequent isolation and purification of the constituents of the weakly acidic fraction.Results:It was shown that the maximum effect of the weakly acidic fraction was obtained at 24 hours after administration and was found to be statistically comparable with that of the positive control.The phytochemical analysis revealed the presence of steroids,terpenoids, alkaloids,flavonoids,glycosides,carbohydrates,saponins,and acidic compounds in the crude extract and carbohydrates,flavonoids.terpenoids and oil in the weakly acidic fraction.Further purification of the weakly acidic fraction of the methanol extract using thin layer chromatography shows that toluene:methanol:diethyl amine(3:1:1) and chloroform:methanol:diethyl amine (9:1:1) are the best solvent system for the isolation of the various components of the weakly acidic fraction of the crude methanol extract of Loranlhus micranthus.Conclusions:The present study has led to the conclusion that the weakly acidic fraction of the plant under study has the potent antidiabetic activity and that the various components can be isolated using basic chromatographic techniques.

Seasonal variation for the antidiabetic activity of Loranthus micranthus methanol extract

Objective:To determine the season in which the Eastern Nigeria mistletoe,Loranthus micranthus,parasitic on Persea americana possesses optimum antidiabetic activity and to determine the seasonal variation in the constituents.Methods:The antidiabetic activities of the aqueous methanol extracts of the leaves of Eastern Nigeria mistletoe,Loranthus micranthus, harvested in two seasons of the year,the onset of rainy season(April) and the peak of rainy season(July) were compared.The tests were carried out on six(6) groups(A-F) of alloxaninduced diabetic rats.Groups A and B received 200 mg/kg and 400 mg/kg of the April sample extracts respectively while groups C and D received same doses of the July sample extracts. Group E and F which were the positive and negative controls received 10 mg/kg of glibenclamide and 2 ml/kg of 3%tween 20 respectively.The blood glucose levels of the animals were monitored hourly with a glucometer for six hours.The phytochemical analysis of the plant extracts were also carried out by standard procedures.Results:The results showed that group A and B exhibited significant(P【0.05) percentage reduction in the fasting blood sugar(FBS) level of the animals(38.9%and 39.2%respectively) with maximum reduction observed at the 5th and 6th hour respectively compared to glibenclamide(71.3%).Group C showed no significant (P】0.05) FBS reduction(15.9%) while group D exhibited highly significant(P【0.01) reduction (47.5%) with the maximum reduction occurring after 6 hours.The phytochemical analysis of the crude methanol extracts revealed the presence of carbohydrates,glycosides,saponins, tannins,flavonoids,steroids,terpenoids,acidic compounds,resins and oils.These were present in different proportions in both seasons.Conclusions:This study shows that there is a seasonal, dose-dependent variation in the chemical composition viz-a-viz the antidiabetic activity of the plant under study.This activity is highest at the peak of the rainy season.

Main immunomodulatory constituents of Eastern Nigeria Mistletoe,Loranthus micranthus Linn

Objective:In our continued efforts to isolate the active immunomodulatory and antiviral constituents of Loranthus micranthus Linn parasitic on Kola acuminata,we set out to fractionate the crude aqueous methanol extract of the plant.The establishment of the most potent fraction(s) as well as the isolation of the pure active secondary metabolite responsible for the immune stimulatory and antiviral activities in Eastern Nigeria mistletoe has become very needful.This will enable us prove our assumption that this particular specie is different from the European version,Viscum album.Methods:Five solvents of varying polarity namely n-hexane,chloroform, ethylacetate,acetone and methanol were successively employed in the complete fractionation of the crude aqueous -methanol extract of Eastern Nigerian mistletoe,Loranthus micranthus Linn.,harvested from Kola acuminata in that order.The fractions were dried in-vacuo using a rotary evaporator maintained at a temperature of(40±5)℃.The different fractions were screened for immunomodulatory activity using a universal model:the cellular - mediated delayed type hypersensivity test in experimental mice.This was performed by administering two different dose levels:250 mg/kg and 500 mg/kg of each fraction against standard positive and negative control. Results:Results of the study established dose-dependent immunostimulatory(upregulatory) effects of the five fractions of the extract as the model used in the study with different percentage stimulations compared to controls.At the dose levels of 500 mg/kg and 250 mg/kg body weight,the percentage stimulation observed were as following:chloroform fraction 311.11%and 122.22%,ethyl acetate fraction 193.38%and 95. 56%,n-hexane 155.56%and 3.50%,acetone fraction 95.56%and 51.11%and methanol fraction 68. 89%and 24.44%respectively.Levamisole,a known potent immunostimulant,afforded a stimulation of 68. 89%at a dose of 2.5 mg/kg.Conclusion:The study showed that the order of immunomodulatory potency is chloroform fraction > ethylacetate fraction > hexane fraction > acetone fraction > methanol fraction.Bioassayguided fractionation and purification of the active extracts led to the isolation of pure compounds phytochemically characterized as sterols and flavonoids.This work indicates that the main constituents of our local mistletoe responsible for immunostimulation are the flavonoids,terpenoids and or steroids.Glycosides,carbohydrates, tannins and alkaoids appear to augment the measured activities.

Immunomodulatory activity of a lupane triterpenoid ester isolated from the eastern Nigeria mistletoe,Loranthus micranthus(Linn)

Objective:To provide further evidence for the ethnomedicinal use of the Eastern Nigeria mistletoe,Loranthus micranthus(L.micranthus),as an immunostimulant.Methods:Solvent fractions from the crude extract of the mistletoe plant was obtained and screened by the cell mediated delayed type hypersensitivity reaction(DTHR) model in mice.Then the immunomodulatory potentials of a major lupane triterpenoid ester isolated from an active hexane fraction of the Eastern Nigeria mistletoe was investigated.Three lupeol-based triterpenoid esters: 7β15α-dihydroxyl-lup-20(29)-ene-3β-palmitate(Ⅰ),7β,15α-dihydroxyl-lup-20(29)- ene-3β-stearate(Ⅱ) and 7β,15α-dihydroxyl-lup-20(29)-ene-3β-decadecanoate(Ⅲ) were isolated from the plant leaves epiphyting on a local kola nut tree and were characterized. Compound 1 was subjected to cell proliferation studies using C57H1/6 splenocvtes at three dose levels(5.25 and 100μg/mL) in presence of controls.Furthermore,the effect of this compound on IL-8 receptor expression was evaluated at three doses(1,5 and 10μg/mL) using the real time polymerase chain reaction assay.Results:This triterpenoid ester produced some enhancement of the splenocytes at the tested doses but at doses higher than 5μg/mL caused inhibition of the IL-8 receptor expression.Conclusions:The present findings support the ethnomedicinal use of the Eastern Nigeria Mistletoe in the management of diseases affecting the immune system.The trilerpenoid(s) have some immunomodulatory abilities on splenocytes and IL-8 receptors and may partly account lor the overall immunomodulatory activity of this plant.

Antimotility effects of extracts and fractions of Eastern Nigeria mistletoe(Loranthus micranthus Linn)

Objective:To evaluate the antimotility activity of Eastern Nigerian mistletoe[Loranthus micranthus（L.micranthus） Linn]parasitic on six different host trees viz.Baphia nitida,Persia americana,Kola accuminata,Irvingia gabonensis,Citrus simensis and Pentacletra macrophylla （P.mycrophylla）.Methods:The antimotility of the methanol extracts and solvent fractions were evaluated in castor oil induced diarrheoa in rats.Results:The methanol extracts（200 mg/kg, i.p.） inhibited defeacation significantly（P 【 0.05） 4 h after administration（75.73%to 93.33%） more than that of atropine sulphate（2 mg/kg,i.p.） which inhibited defeacation by 80.0%.The methanol extract（200 mg/kg,i.p.） of L micranthus parasitic on P.mycrophylla exhibited significant（P【0.05） inhibition in gastrointestinal transit（67.6%） more than that of atropine sulphate（2 mg/kg,Lp.） which inhibited gastrointestinal transit by 26.4%.The solvent fractions of L micranthus parasitic on P.mycrophylla at dose levels of 150 mg/kg inhibited significantly the gastrointestinal transit of mice.Fraction F5 exhibited inhibitory activity which was comparable to loperamide（73.3%）. Conclusions:The methanol extract of L micranthus parasitic on P.macrophylla exhibits higher antimotility activity that other extracts.The solvent fractions could serve as source of novel antimotility agents.

Immunomodulation and Nigerian mistletoe immunomodulatory activities of n-hexane and methanol extracts of Loranthus micranthus Linn,parasitic on Parkia biglobosa.

Loranthus micranthus is the species of mistletoe peculiar to the eastern province of Nigeria.It has been shown to possess anti-diabetic,anumotility,antimicrobial and antihypertensive activities which are host-tree dependent. The antimicrobial activity was found to vary with the season during which the plant was harvested.We are of the opinion that this species should possess immunomodulating potentials as have been reported for the European species,Viscum album.In our efforts to establish the bio-activities and active principles in our local mistletoe, the immunomodulatory activity of n-hexane and methanol extracts from Loranthus micranthus parasitic on Persea americana was assessed at three dose levels ranging from 100 to 400 mg/kg body weight using delayed type hypersensitivity reaction(DTHR) and cyclophosphamide-induced myelosuppression models in mice.This was compared with responses from a standard immunostimulatory drug,levamisole.Preliminary phytochemical analysis of the plant showed the presence of tannins,flavonoids,alkaloids,terpenoids,carbohydrates and saponins.Regression analysis indicated a dose-dependent response relationship in the parameters measured with over 170%increase for both extracts at the highest dose level.The one way ANOVA test showed significant variation in the parameters between the controls and the different dose levels.However,at 95%confidence level,(P【0.05),there was no statistically significant difference between the two extracts, an indication that the active immunomodulant(s) could be both in the polar and non-polar crude extract.In conclusion,the present results have established some immune stimulating actions of the Eastern Nigeria mistletoe, Loranthus micranthus thus indicating that this variant of the semi parasitic plant holds a strong promise as an immunostimulatory candidate.There is therefore,a basis for further detailed investigation on the fractions and specific constituents.Thus,these extracts from Loranthus micranthus possess pronounced immune stimulating action comparable to Levamisole in mouse-based models.

Two New Abietane Quinones from Isodon lophanthoides var. Micranthus

The structures of two new abietane quinones, named micranthins A and B, were determined to be 7a-methoxy-14, 16-epoxy-8, 13-abietadiene-11, 12-dione (1) and 16-acetoxy-6, 7-dehydroroyleanone (2) respectively, which were isolated from Isodon lophanthoides var. micranthus.

超声波处理对羽扇豆种子活力及生理特性的影响

采用超声波处理羽扇豆(Lupinus micranthus Guss.)种子,对羽扇豆种子的发芽势、发芽率、活力指数、种子浸出液的相对电导率和幼苗的超氧化物歧化酶(SOD)活性、可溶性蛋白含量、丙二醛(MDA)含量等进行了测定。结果表明,经过超声波处理的羽扇豆种子的发芽势、发芽率都得到了提高,以20 min的处理时间为最佳;处理后提高了羽扇豆幼苗的SOD活性和可溶性蛋白含量,降低了幼苗MDA含量和种子浸出液的相对电导率,提高了种子活力。说明羽扇豆种子萌发之前采用适宜的短时间超声波处理,不仅能促进萌发,还能促进其抗氧化能力的提高。

温度及基质对羽扇豆种子发芽的影响

通过测定不同温度和基质条件下羽扇豆(Lupinus micranthus Guss.)种子的发芽率、发芽势、生长量以及幼苗生长过程,分析温度和基质对羽扇豆种子萌发的影响。结果表明,温度对种子萌发和幼苗生长影响明显,是羽扇豆种子萌发与幼苗生长最重要的环境因子,15℃最利于获得较高发芽率,25℃最有利于获得高生长量;基质对羽扇豆的最大生长量影响极显著,对发芽始期和发芽势影响显著,对发芽率、发芽末期、发芽时间和平均日生长量影响不显著,最具综合优势的基质是珍珠岩,蛭石最有利于幼苗的生长;温度与基质对发芽率、发芽期指标、发芽势和最大生长量有明显交互作用,温度与基质的最优处理是“15℃+本地黄心土”和“15℃+草炭”。