Sterols (beta-sitosterol and stigmasterol), sterol glycosides (3-O-beta-D-glucopyranosyl beta-sitosterol, 3-O-beta-D-glucopyranosyl stigmasterol), nonadecane, phytyl valerate, adenosine, kaempferol-3-O-neohesperidoside, methyl hexadecanoate, methyl 9-octadecenoate, 4-hydroxy-4-methyl-2-pentanone, stigmasterol acetate, quercetin, kaempferol-3-glucoside, quercetin-3-O-rhamnosyl(1-6)galactoside, quercetin-3-O-rhamnosyl(1 -6)glucoside, 3,5-di-O-caffeoyl quinic acid, 4,5-di-O-caffeoylquinic acid, 1,2-bis-dodecanoyl-3-alpha-O-D-glucopyranosyl-Sn-glycerol.(1
Gynura procumbens (Merr.) Compositae is an annual evergreen shrub with a fleshy stem with a purple tint. In South East Asia, especially, Indonesia, Malaysia, and Thailand, the plant is considered to be of considerable medicinal value. In Thailand, it has been used traditionally as a topical anti-inflammatory and anti-allergy agent.(7
) In Indonesia, the stem and leaves are used as an antipyretic in eruptive fevers. The dried leaves rubbed with oil and mashed are used as a salve for rashes. Gynura procumbens is also used as a remedy for kidney trouble and hypertension.(8
In Malaysia, the plants are widely used in folk medicine to self medicate a variety of conditions and ailments ranging from migraines, constipation, hypertension, diabetes mellitus, and cancer. For the Chinese community in Malaysia, this plant has earned its common name, bai bing cao (meaning hundred ailments plant), among the enthusiasts of the Chinese community. Use of this plant for similar complaints is gaining popularity among the Malays.(9) Information regarding the pharmacognosical evaluation of the leaves is reported in the Malaysian Herbal Monograph Volume 2.(10)
Safety in the young and elderly persons has not been established.
Gynura procumbens leaves have been reported to show hypoglycaemic effects in laboratory animals.(13
) The ethanol extract of Gynura procumbens was reported to show anti-hyperglycaemic and anti-hyperlipidaemic activities in diabetic rats. The extract showed effects similar to metformin by improving glucose tolerance in STZ-induced diabetic rats, but these results were not seen in normal rats. Therefore, the extract may have activity similar to biguanide agents.
Hypoglycaemic activity of Gynura procumbens following serial extraction and fractionation was also reported.(14),(15),(16) The methanol extract and n-butanol fraction(17),(18) exerted a significant hypoglycaemic effect when administered orally to streptozotocin-induced diabetic rats.
Repeated screening of petroleum ether and methanol extracts respectively on normal rats, neither of the extracts reduced blood glucose levels. However, the methanol extract was found to significantly reduce the blood glucose levels of streptozotocin-induced diabetic rats.(19) Similarly in a glucose tolerance test where rats were loaded with glucose 500mg/kg intraperitoneally to induce hyperglycaemia, only the methanol extract inhibited the rise in glucose levels. In addition, fractionation of the methanol extract into chloroform, ethyl acetate, n-butanol, and aqueous fractions showed that only ethyl acetate caused a significant anti-hyperglycaemic effect in rats loaded with glucose and a reduction in the blood glucose levels of streptozotocin-induced diabetic rats.(20)
Studies also reported that Gynura procumbens in an ethanolic extract possessed anti-herpes simplex viral activity, in vitro. The powdered whole plant was successively extracted with petroleum ether, chloroform, and ethanol. Bio-assay-guided fractionation of the ethanolic extract resulted in the isolation of a mixture of 3,5-di-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid as the active components. The extract showed virucidal and anti-replicative activity with IC50 of 96.0 and 61.0 mg/ml against HSV-2, respectively. Other compounds found to posses anti-HSV activity included mixtures of phytosterols and their glycosides as well as a glycoglycerolipid, namely 1,2-bis-dodecanoyl-3-alpha-D-glucopyranosyl-Sn-glycerol, with an IC50 of 40.0mg/ml against HSV-2.(21)
Gynura procumbens was screened for anti-inflammatory activity using a croton oil-induced inflammation in the ears of mice.(22) The ethyl acetate fraction of the ethanolic extract significantly inhibited the increase in ear thickness in response to the croton oil. The activity of 0.75mg/ear of the ethyl acetate fraction showed similar anti-inflammatory activity (inhibition 62.5%) to that of 6 mg/ear hydrocortisone 21-hemisuccinate sodium salt (inhibition 64.8%). On further fractionation, hexane and toluene sub-fractions showed significant inhibitions of 44.6% and 34.8%, respectively. These two fractions had similar activities to 4mg/ear of hydrocortisone (inhibition 35.0%). The petroleum ether extract of Gynura procumbens also reported analgesic and anti-inflammatory activities by inhibiting oedema and hyperalgesia in the treated animals with carrageenan.(23)
A preliminary liver metabolism study, reported that the petroleum ether extract of Gynura procumbens could increase the metabolism of aminopyrine on adult male rats at a concentration of 100mg/ml. However the chloroform fraction of the methanol extract reduced the metabolism of aminopyrine on young female rats at a concentration of 10mg/ml, 1mg/ml, and 100ng/ml respectively.(24)
The plant is also reported to lower blood pressure. Anaesthetized rats, weighing 250-300g, were given intravenous bolus injections of pH 7.4-adjusted aqueous extracts of the plant at various concentrations. Results showed that aqueous extracts of the plant consistently and significantly (p<0.01) decreased the systolic blood pressure of the rats at doses ranging from 32.5mg/ml to 260.0mg/ml. In addition, changes in the blood pressure when injected with the dose of 32.5mg/ml was significantly (p<0.05) lower than that obtained when injected with the dose of 32.5mg/ml. The diastolic blood pressure was similarly decreased (at 32.5mg/ml, p<0.05; at 260.0mg/ml, p<0.01) by these injections. Thus, the mean arterial pressure was markedly (p<0.01) decreased by this treatment. Although the heart rate decreased when injected with the higher dose (260.0mg/ml), it was not significant when compared with the pre-injection rate. Thus, the aqueous extracts of the plant have been demonstrated to have some hypotensive properties.(25) Research in the cardiovascular effects on isolated organs of rats found that Gynura procumbens extract inhibited noradrenaline induced-contraction of isolated rats aorta, and also inhibited isoprenaline-induced inotropic activity (increase in contraction) of the left atria The results thus support that Gynura procumbens may lower blood pressure as traditionally claimed.(26)
Uses reported in folk medicine, but not supported by clinical data
Gynura procumbens has been used for: inflammation, allergies, migraines, constipation, blood sugar regulation, rheumatism, hypertension, kidney problems, anti-herpes, anti-viral, and colon cancer.