Screening of antioxidant activity of three Indian medicinal plants, traditionally used for the management of neurodegenerative diseases

Ethnomedicines used in Trinidad and Tobago for urinary problems and diabetes mellitus

BACKGROUND

This paper is based on ethnobotanical interviews conducted from 1996-2000 in Trinidad and Tobago with thirty male and female respondents.

METHODS

A non-experimental validation was conducted on the plants used for urinary problems and diabetes mellitus: This is a preliminary step to establish that the plants used are safe or effective, to help direct clinical trials, and to inform Caribbean physicians of the plants' known properties to avoid counter-prescribing.

RESULTS

The following plants are used to treat diabetes: Antigonon leptopus, Bidens alba, Bidens pilosa, Bixa orellana, Bontia daphnoides, Carica papaya, Catharanthus roseus, Cocos nucifera, Gomphrena globosa, Laportea aestuans, Momordica charantia, Morus alba, Phyllanthus urinaria and Spiranthes acaulis. Apium graviolens is used as a heart tonic and for low blood pressure. Bixa orellana, Bontia daphnoides, Cuscuta americana and Gomphrena globosa are used for jaundice. The following plants are used for hypertension: Aloe vera, Annona muricata, Artocarpus altilis, Bixa orellana, Bidens alba, Bidens pilosa, Bonta daphnoides, Carica papaya, Cecropia peltata, Citrus paradisi, Cola nitida, Crescentia cujete, Gomphrena globosa, Hibiscus sabdariffa, Kalanchoe pinnata, Morus alba, Nopalea cochinellifera, Ocimum campechianum, Passiflora quadrangularis, Persea americana and Tamarindus indicus. The plants used for kidney problems are Theobroma cacao, Chamaesyce hirta, Flemingia strobilifera, Peperomia rotundifolia, Petiveria alliacea, Nopalea cochinellifera, Apium graveolens, Cynodon dactylon, Eleusine indica, Gomphrena globosa, Pityrogramma calomelanos and Vetiveria zizanioides. Plants are also used for gall stones and for cooling.

CONCLUSION

Chamaesyce hirta, Cissus verticillata, Kalanchoe pinnata, Peperomia spp., Portulaca oleraceae, Scoparia dulcis, and Zea mays have sufficient evidence to support their traditional use for urinary problems, "cooling" and high cholesterol. Eggplant extract as a hypocholesterolemic agent has some support but needs more study. The plants used for hypertension, jaundice and diabetes that may be safe and justify more formal evaluation are Annona squamosa, Aloe vera, Apium graveolens, Bidens alba, Carica papaya, Catharanthus roseus, Cecropia peltata, Citrus paradisi, Hibsicus sabdariffa, Momordica charantia, Morus alba, Persea americana, Phyllanthus urinaria, Tamarindus indicus and Tournefortia hirsutissima. Several of the plants are used for more than one condition and further trials should take this into account.

Safety of traditional arab herbal medicine

Herbal remedies are widely used for the treatment and prevention of various diseases and often contain highly active pharmacological compounds. Many medicinal herbs and pharmaceutical drugs are therapeutic at one dose and toxic at another. Toxicity related to traditional medicines is becoming more widely recognized as these remedies become popular in the Mediterranean region as well as worldwide. Most reports concerning the toxic effects of herbal medicines are associated with hepatotoxicity although reports of other toxic effects including kidney, nervous system, blood, cardiovascular and dermatologic effects, mutagenicity and carcinogenicity have also been published in the medical literature. This article presents a systematic review on safety of traditional Arab medicine and the contribution of Arab scholars to toxicology. Use of modern cell biological, biochemical, in vitro and in vivo techniques for the evaluation of medicinal plants safety is also discussed.

Screening of antihelminthic effects of Indian plant extracts: a preliminary report

INTRODUCTION

The purpose of the present study was to evaluate the antihelminthic effect of plants from the Ayurvedic system of medicine traditionally used in India.

MATERIALS AND METHODS

Six plant extracts were assayed for their activity against free-living nematodes. Inhibitory effects on free-living nematodes were evaluated in vitro using aqueous or ethanolic extracts.

CONCLUSIONS

Of six plants assayed, Momordica charantia yielded the best results, its crude extract producing 96% mortality.

Characterization of the phenolic constituents in Mauritian endemic plants as determinants of their antioxidant activities in vitro

The phenolic constituents of Mauritian endemic plants from the Rubiaceae and Myrtaceae family were assessed and correlated with their potential antioxidant activities in vitro. The antioxidant activities of the plant extracts ranged from 0.27 to 1.49mmol Trolox equivalent/g FW and from 0.20 to 1.39mmol Fe(II) equivalent/g FW in the TEAC and FAP assays, respectively, with Syzygium commersonii showing the highest activity in these two systems. Eugenia orbiculata and all the Syzygium species were effective scavengers of hypochlorous acid while Monimiastrum acutisepalum was the most potent inhibitor of deoxyribose degradation. The plant extracts inhibited microsomal lipid peroxidation with low IC(50)s ranging from 0.02 to 1.75mgFW/mL when reaction was initiated with Fe(3+)/ascorbate and from 0.093 to 1.55mgFW/mL in the AAPH-dependent lipid peroxidation. The potential prooxidant nature of the plant extracts was compared with ascorbate (250microM) using copper-phenanthroline assay. The plant extracts at concentrations up to 5gFW/L were not prooxidant. However, Myonima nitens, Syzygium commersonii, Syzygium glomeratum and Syzygium mauritianum at concentrations of 10gFW/L had potency approaching 50% of the prooxidant activity of ascorbic acid in vitro, suggesting relative safeties. The total phenolics influenced the antioxidant activities in the TEAC, FRAP and HOCl scavenging assays whereas a negative correlation was observed with the deoxyribose assay. The high levels of polyphenolic compounds and the significant antioxidant activities of these Rubiaceae and Myrtaceae plant family make them suitable candidates as prophylactic agent.

The protective effects of Achillea L. species native in Turkey against H(2)O(2)-induced oxidative damage in human erythrocytes and leucocytes

The aim of the present study was to investigate the protective effects of infusions prepared from 15 Achillea (Asteraceae) species against H(2)O(2)-induced oxidative damage in human erythrocytes and leucocytes used in traditional Turkish medicine. CAT, SOD and GPx activities, effects of LPO and GSH levels of the infusions on erythrocytes and leucocytes were assessed. The results indicated that all infusions of Achillea species were effective on antioxidant enzyme systems of erythrocytes and leucocytes when compared with H(2)O(2) group. Achillea falcata was the most effective one on CAT, GPx and SOD enzyme systems of erythrocytes. Among plant infusions, Achillea crithmifolia and Achillea nobilis subsp. neilrechii showed the highest activities on CAT, while Achillea millefolium subsp. pannonica on SOD, Achillea teretifolia on GPx and Achillea nobilis subsp. sipylea on LPO enzyme systems of leucocytes. The present results demonstrate that infusions of Achillea species are a potential source of natural antioxidants for treatment and prevention of diseases in which LPO takes place.

A review of antioxidants and Alzheimer's disease

BACKGROUND

In this article, we review a diverse body of research and draw conclusions about the usefulness, or lack there-of, of specific antioxidants in the prevention of Alzheimer's disease (AD).

METHODS

The National Library of Medicine's database was searched for the years 1996-2004 using the search terms "Alzheimer's, anti-oxidants, antioxidants."

RESULTS

Over 300 articles were identified and 187 articles were selected for inclusion based on relevance to the topic. Agents that show promise in helping prevent AD include: 1) aged garlic extract, 2) curcumin, 3) melatonin, 4) resveratrol, 5) Ginkgo biloba extract, 6) green tea, 7) vitamin C and 8) vitamin E.

CONCLUSIONS

While the clinical value of antioxidants for the prevention of AD is often ambiguous, some can be recommended based upon: 1) epidemiological evidence, 2) known benefits for prevention of other maladies, and 3) benign nature of the substance. Long-term, prospective studies are recommended.

Alcoholic stem extract of Coscinium fenestratum regulates carbohydrate metabolism and improves antioxidant status in streptozotocin-nicotinamide induced diabetic rats

Alcoholic extract of the stems of Coscinium fenestratum, a medicinal plant indigenous to India and Sri Lanka used in ayurveda and siddha medicine for treating diabetes, was studied for its carbohydrate metabolism effect and antioxidant status in streptozotocin-nicotinamide induced type 2 diabetic rats. Oral administration of C. fenestratum stem extract in graded doses caused a significant increase in enzymatic antioxidants such as catalase, superoxide dismutase, glutathione synthetase, peroxidase, and glutathione peroxidase and in the nonenzymatic antioxidants ascorbic acid, ceruloplasmin and tocopherol. Effects of alcoholic extract on glycolytic enzymes such as glucose-6-phosphate dehydrogenase, lactate dehydrogenase and hexokinase showed a significant increase in their levels, whereas a significant decrease was observed in the levels of gluconeogenic enzyme, glucose-6-phosphatase and alanine aminotransferase in treated diabetic rats. Serum creatinine and urea levels also declined significantly. This investigation demonstrates significant antidiabetic activity of C. fenestratum.

Antioxidant approach to disease management and the role of 'Rasayana' herbs of Ayurveda

The disease preventive and health promotive approach of 'Ayurveda', which takes into consideration the whole body, mind and spirit while dealing with the maintenance of health, promotion of health and treating ailments is holistic and finds increasing acceptability in many regions of the world. Ancient Ayurvedic physicians had developed certain dietary and therapeutic measures to arrest/delay ageing and rejuvenating whole functional dynamics of the body system. This revitalization and rejuvenation is known as the 'Rasayan chikitsa' (rejuvenation therapy). Traditionally, Rasayana drugs are used against a plethora of seemingly diverse disorders with no pathophysiological connections according to modern medicine. Though, this group of plants generally possesses strong antioxidant activity, only a few have been investigated in detail. Over about 100 disorders like rheumatoid arthritis, hemorrhagic shock, CVS disorders, cystic fibrosis, metabolic disorders, neurodegenerative diseases, gastrointestinal ulcerogenesis and AIDS have been reported as reactive oxygen species mediated. In this review, the role of free radicals in these diseases has been briefly reviewed. 'Rasayana' plants with potent antioxidant activity have been reviewed for their traditional uses, and mechanism of antioxidant action. Fifteen such plants have been dealt with in detail and some more plants with less work have also been reviewed briefly.

Genotoxic potentiality of aqueous extract prepared from Chrysobalanus icaco L. leaves

Plants have been related to our lives, being used as medicine, regardless of scientific evidence of side effects. This work analyses the toxicological effects of Chrysobalanus icaco L. aqueous extract, used in different pathologies. It was studied through: (i) alteration of plasmid pUC 9.1 topology; (ii) survival of bacterial strains submitted, or not, to previous treatment with SnCl2; (iii) transformation efficiency of E. coli strain by the treatment with the plasmid pUC 9.1. In (i), the treatment of the plasmid resulted in DNA single-strand breaks (SSB). A decrease of the lethal effect induced by SnCl2 in presence of the extract was found, while no C. icaco bacterial survival reduction was observed. The transformation efficiency of the plasmid was also reduced. Results suggest that the extract could present a potential genotoxic effect, as demonstrated either by the induction of SSB in plasmid or in transformation efficiency experiments. Finally, it presents an antioxidant action.

Cytoprotection by Achyrocline satureioides (Lam) D.C. and some of its main flavonoids against oxidative stress

Epidemiological studies indicate that dietary antioxidants can influence the incidence of neurodegenerative diseases. Among them flavonoids have been proposed to be effective cytoprotectors. Consequently, herbs with a high concentration of these compounds such as Achyrocline satureioides, Ginkgo biloba and Epilobium parviflorum are of special interest. In this context a comparative study of the cytoprotective capacity of infusions from the three plants against an oxidative insult was performed. Hence, the cytoprotective activity of each infusion against H2O2 injury to PC12 cells was tested and the antioxidant capacity was assessed by the ABTS*+ radical bleaching assay. Free and glycosylated flavonoids contained in the infusions were identified by HPLC and the cytoprotective effect of some of these individual flavonoids was tested. The analysis of the flavonoid content of the infusions revealed different profiles. Epilobium parviflorum infusion showed the highest antioxidant capacity but only Achyrocline satureioides infusion proved to be cytoprotective. Moreover, the free flavonoids quercetin and luteolin contained in this infusion were also cytoprotective. In conclusion, the free radical scavenger capacity did not correlate with the cytoprotective profile of the infusions. The special mixture of unglycosylated Achyrocline satureioides flavonoids could be a clue to explain the unique effect of this plant.

Toxicological investigation of aqueous-methanolic extract of the calyces of Hibiscus sabdariffa L

The aqueous fraction of an aqueous-alcoholic extract of Hibiscus sabdariffa L. calyces was given to Wistar albino rats (150-200g) orally as drugs to study the toxicity of the extract. The rats, which were fed with commercial diet and water ad libitum, were divided into six groups of four rats each. Treatments 1 through 6 received 0, 1, 3, 5, 10 and 15 doses of 250 mg/kg each, respectively; the control group received physiological saline (0.9% NaCl). Results of the studies showed that the levels of serum aspartate aminotransferase (AST) and alanine amino transferase (ALT) were significantly (P<0.05) increased in all the treatments compared with the control group. However, the serum levels of alkaline phosphatase, and lactate dehydrogenase were not significantly (P>0.05) affected. Only the group with 15 doses had their serum level of albumin significantly (P<0.05) increased. However, the results of histopathological studies showed that both the livers and hearts gave no pathological features for all the treatments. The results showed that prolong usage of this extract at 15-dose level could cause liver injury while the effect was mild at small dose levels (1-10). Though the average consumption of 150-180 mg/kg per day appears safe, the extract should be taken with caution bearing in mind that higher doses could affect the liver.

Cell culture protection and in vivo neuroprotective capacity of flavonoids

Flavonoids are an important group of recognized antioxidants ubiquitous in fruits, vegetables and herbs. There are epidemiological evidences for the stroke-protecting capacity of flavonoids and while the neuroprotective power of complex extracts rich in flavonoids like those of Ginkgo biloba, green tea or lyophilized red wine have been demonstrated in several studies, neuroprotection by individual flavonoids has been poorly studied in vivo. The neuroprotective capacity of individual flavonoids was studied in PC12 cells in culture and in a model of permanent focal ischemia (permanent Middle Cerebral Artery Occlusion - pMCAO). In the in vivo experiments, flavonoids were administered in lecithin preparations to facilitate the crossing of the blood brain barrier. The simultaneous incubation of PC12 cells with 200 micro M hydrogen peroxide (H2O2) and different flavonoids for 30 min resulted in a conspicuous profile: quercetin, fisetin, luteolin and myricetin significantly increased cell survival while catechin, kaempherol and taxifolin did not. Quercetin was detected in brain tissue 30 min and 1 h after intraperitoneal administration. When one of the protective flavonoids (quercetin) and one of those that failed to increase PC12 cell survival (catechin) were assessed for their protective capacity in the pMCAO model, administered i.p. 30 min after vessel occlusion, quercetin significantly decreased the brain ischemic lesion while catechin did not. It is concluded that when administered in liposomal preparations, flavonoids structurally related to quercetin could become leads for the development of a new generation of molecules to be clinically effective in human brain ischemia.