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Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on their structure. Flavonoids are present in food and medicinal plants and are thus consumed by humans. They are found in plants as glycosides. Before oral absorption, flavonoids undergo deglycosylation either by lactase phloridzin hydrolase or cytosolic ß-glucocidase. The absorbed aglycone is then conjugated by methylation, sulphatation or glucuronidation. Both the aglycones and the conjugates can pass the blood-brain barrier. In the CNS several flavones bind to the benzodiazepine site on the GABA(A)-receptor resulting in sedation, anxiolytic or anti-convulsive effects. Flavonoids of several classes are inhibitors of monoamine oxidase A or B, thereby working as anti-depressants or to improve the conditions of Parkinson's patients. Flavanols, flavanones and anthocyanidins have protective effects preventing inflammatory processes leading to nerve injury. Flavonoids seem capable of influencing health and mood.

ETHNOPHARMACOLOGICAL RELEVANCE: : Anagallis arvensis and Anagallis foemina are traditionally used in Navarra (Spain) for dermatological purposes regarding wound healing properties. In some cases they are also used to threat internal infections although they are known to be toxic at high doses. AIM OF STUDY: : Due to lack of studies, we decided to evaluate the potential of the plants as wound healing remedies measuring antimicrobial and anti-inflammatory properties using in vitro procedures. MATERIALS AND METHODS: Antimicrobial effects were studied against four bacteria and one fungus. Anti-inflammatory properties were measured in terms of COX-1 and -2 inhibition as well as superoxide radical scavenging capacity. RESULTS: Both species exerted antimicrobial and anti-inflammatory effects. The methanolic extract obtained from Anagallis arvensis seemed to produce the highest inhibition in Candida albicans (MIC=0.31mg/ml). Inhibition of COX-1 and -2 was also stronger for methanolic extracts whereas aqueous were revealed as better free radical scavengers. CONCLUSIONS: The study reveals that both species posses antimicrobial and anti-inflammatory activities related to their ethnomedicinal uses.

Interest from the dairy industry in adding herbal drugs to milk and yogurt products raises the question of whether these plant materials can be pasteurized. Root material of Rhodiola rosea, Eleutherococcus senticosus, and Panax ginseng, all plants with adaptogenic activities, was pasteurized. The content of active compounds in the root material before and after pasteurization was quantified by HPLC analysis. The results show that the eleutherosides in E. senticosus, and to an extent the ginsenosides from P. ginseng, could withstand pasteurization, whereas salidroside and rosavin from R. rosea did not survive pasteurization. Thus, R. rosea is not suitable for products requiring pasteurization.

Searsia species are used in South Africa to treat epilepsy. Previous studies have demonstrated an in vitro N-methyl-D-aspartic acid (NMDA) receptor antagonistic effect of the ethanolic leaf extract. The aim of this study was to evaluate the potential anticonvulsant properties of the ethanolic extract of S. dentata in various animal models of epilepsy. The extract was submitted to a screening in anticonvulsant assays including NMDA-, kainic acid (KA)-, pentylenetetrazol (PTZ)- and bicuculline (BIC)-induced seizures in rats. The extract protected 47% of the PN 18 Wistar pups (postnatal day 18, date of birth PN 0) (p < 0.05, n > 10) against NMDA-induced seizures and significantly delayed the onset of PTZ-induced seizures (p < 0.05, n > 8) at a dose of 250 mg/kg. A dose optimum was detected at 500 mg/kg for protection against KA-(63% protection, p < 0.05, n > 8) and BIC-induced seizures (50% protection, p < 0.05, n > 8) in young adult and PN 18 rats, respectively. The ethanolic extract of S. dentata showed anticonvulsive properties in several models of epilepsy. These results are compatible with previous findings of NMDA receptor antagonism. Due to the complex composition of the extract, the effect might be caused by more than one compound. Copyright (c) 2009 John Wiley & Sons, Ltd.

Phlomis lychnitis L. (Lamiaceae) is consumed as a traditional herbal tea in Spain. The antioxidant-protective effects as well as its phytoconstituents have never been established. The ability of the methanolic extract to protect cells from oxidative stress was evaluated in rat pheochromocytoma cells (PC12) using hydrogen peroxide as toxic agent. The viability of PC12 cells pre-treated with the methanolic extract of Phlomis lychnitis, determined by the MTT and LDH assays, was significantly improved at the highest dose (p < 0.01). The antioxidant activity was confirmed evaluating the capacity of the plant to scavenge ABTS, DPPH, O(2) . (-) radicals and to inhibit XO. Bioassay guided fractionation led to antioxidant compounds. Qualitative HPLC/DAD/ESI/MS analysis reported phenylpropanoids, verbascoside being the major antioxidant constituent.

Mints are aromatic plants with a tradition as medicinal remedies and culinary herbs. With the aim of investigating potential central nervous system (CNS) activities of traditional medicinal plants, four species and one hybrid of the genus Mentha (M. aquatica, M. longifolia, M. pulegium, M. suaveolens and M. x piperita) were selected. Methanolic extracts of the plants were tested for protective effects against hydrogen-peroxide-induced toxicity in PC12 cells, antioxidant activity (by ABTS and X/XO methods) and neurochemical properties (MAO-A inhibition, AChE inhibition and affinity to the GABA(A) receptor). Mentha x piperita and Mentha aquatica produced significant (p < 0.05) protection of the PC12 cells against oxidative stress. All the plants exhibited antioxidant and MAO-A inhibitory activities, M. x piperita being the most active. M. aquatica showed the highest affinity to the GABA(A)-receptor assay. Results demonstrate that mints might have effect on the CNS. Copyright (c) 2009 John Wiley & Sons, Ltd.

Piper capense L.f. (Piperaceae) is used traditionally in South Africa as a sleep inducing remedy. Bioassay-guided fractionation of the roots of P. capense led to the isolation of piperine (1) and 4,5-dihydropiperine (2), which showed moderate affinity for the benzodiazepine site on the GABA(A) receptor (IC(50) values of 1.2 mM and 1.0 mM, respectively). The present study suggests that strict structural properties of the amides are essential for affinity. Taken together, these observations suggest that the carbon chain must contain not less than four carbons, and that a conjugated double bond, adjacent to the amide group, is necessary for binding to the receptor and that the amine part should be bulky.

Melissa officinalis has traditionally been used due to its effects on nervous system. Both methanolic and aqueous extracts were tested for protective effects on the PC12 cell line, free radical scavenging properties and neurological activities (inhibition of MAO-A and acetylcholinesterase enzymes and affinity to the GABA(A)-benzodiazepine receptor). The results suggest that the plant has a significant (P < 0.05) protective effect on hydrogen peroxide induced toxicity in PC12 cells. The radical scavenging properties were also investigated in cells and in cell free systems, where this plant was shown to be a good free radical scavenger. The MAO-A bioassay was also performed to detect possible antidepressant activities demonstrating that both extracts inhibited this enzyme, which has a key role in neurotransmitters metabolism. However, no activity was detected in the acetylcholinesterase and GABA assays. In general, the methanolic extract was more effective than the aqueous.

Extracts of Tanacetum parthenium are used in the prophylactic treatment of migraine and have also been used in Danish folk medicine for the treatment of epilepsy. An ethanol extract of T. parthenium showed high affinity for the GABA(A)-benzodiazepine site. An ethanol extract of T. parthenium was fractionated by VLC on silica and preparative C18 HPLC. Each step was monitored with the GABA(A)-benzodiazepine bioassay. The fractionation led to the isolation of apigenin, which may be responsible for CNS-effects of T. parthenium extracts. Copyright (c) 2009 John Wiley & Sons, Ltd.

AIM OF THE STUDY: This study investigated MAO-A inhibitory activity of methanol extract of Calluna vulgaris (L.) Hull., which traditionally has been used as a nerve calming remedy. MATERIALS AND METHODS: A methanolic extract of Calluna vulgaris was partitioned against heptane, ethyl acetate and water. The three fractions were tested in a photometric peroxidase linked MAO-A bioassay. The ethyl acetate phase showed the highest MAO-A inhibitory activity. Quercetin was isolated by VLC through bioassay-guided fractionation and purified by re-crystallisation. The structure was elucidated by LC-MS and (1)H NMR. RESULTS: The IC(50)-value for MAO-A inhibition by quercetin was 18+/-0.2muM in an assay where the IC(50)-value for MAO-A inhibition by clorgylin was 0.2+/-0.02muM. CONCLUSION: The content of quercetin in Calluna vulgaris might explain the reported nerve calming effect of the plant.

ETHNOPHARMACOLOGICAL RELEVANCE: Searsia dentata and Searsia pyroides are used in traditional South African medicine to treat convulsions and epilepsy. Previous studies have demonstrated that extracts of these plants comprise compounds that bind to the flumazenil-sensitive site on the GABA(A) receptor. However, their use as anticonvulsant medicinal plants cannot be adequately explained by these findings. AIMS: The aim of this study was to examine the possible involvement of the glutamatergic system of extracts from the plants. MATERIALS AND METHODS: The mouse cortical wedge preparation was used for functional characterization of the extracts. The affinity towards the NMDA and the AMPA receptor was investigated using classical [(3)H]-GP39653 and [(3)H]-AMPA binding assays, respectively. RESULTS: The extracts of Searsia dentata and Searsia pyroides inhibited the spontaneous epileptiform discharges in mouse cerebral cortical slices with ED(50) of 0.62 and 1.67mg dry extract/mL, respectively. Both extracts displaced [(3)H]-GP39653 binding and significantly inhibited the NMDA-induced response during co-administration in cortical slices. CONCLUSION: In this study, the NMDA receptor antagonistic effect of the crude ethanolic extracts of these two South African medicinal plants was demonstrated.

The majority of the population in South Africa use traditional health care to treat various mental conditions. In this review, we present ethnobotanical information on plants used by the traditional healers in South Africa to treat mental illnesses, specifically epilepsy, depression, age-related dementia and debilitative mental disorders. Details of the recent scientific studies conducted on some of these plants are reviewed. Extracts of Searsia chirindensis, Cotelydon orbiculata and Leonotis leonurus have shown in vivo anticonvulsant activity. Extracts from Searsia dentata and Searsia pyroides showed spontaneous epileptiform discharge in mouse cortical slices, and acted as NMDA-receptor antagonists. Apigenin, amentoflavone and agathisflavone with affinity to the benzodiazepine site on the GABA(A)-receptor were isolated from Searsia pyroides. Naringenin with affinity to the GABA(A)-benzodiazepine receptor was isolated from Mentha aquatica. Agapanthus campanulatus, Boophone disticha, Mondia whitei and Xysmalobium undulatum exhibited antidepressant-like activity in three in vivo models for depression. Amaryllidaceae alkaloids with activity to the serotonin transporter were isolated from Boophone disticha. The alkaloid mesembrine, which act as a serotonin reuptake inhibitor, was isolated from Sceletium tortuosum. Investigations of plants used to treat age-related dementia and debilitative mental disorders lead to the isolation of a number of Amaryllidaceae alkaloids with acetylcholinesterase inhibitory activity from Boophone disticha and Crinum species. Extracts of Mentha aquatica, Gasteria croucheri, Ruta graveolens and Scotia brachypetala inhibited MAO-B. Naringenin was isolated from Mentha aquatica as a MAO inhibitor. Only a small number of the more than 300 southern African plant species reported to treat or affect the CNS have been scientifically evaluated. Very few of the active compounds have been isolated and identified.

ETHNOPHARMACOLOGICAL RELEVANCE: The four South African medicinal plants Agapanthus campanulatus (AC), Boophone distica (BD), Mondia whitei (MW) and Xysmalobium undulatum (XU) are used in traditional medicine to treat depression. AIM: To evaluate the effect of ethanolic extracts of the plants in models for depression. MATERIALS AND METHODS: The extracts were screened for affinity for the serotonin transporter (SERT) in the [(3)H]-citalopram-binding assay. The inhibitory potency of the extracts towards the SERT, the noradrenalin transporter (NAT) and the dopamine transporter (DAT) were determined in a functional uptake inhibition assay. Antidepressant-like effects of the extracts were investigated using the tail suspension test (TST) and the forced swim test in both rats (rFST) and mice (mFST). RESULTS: All four plants showed affinity for SERT in the binding assay. AC and BD showed functional inhibition of SERT, NAT and DAT, MW affected SERT while XU showed no effect. BD showed significant effect in the TST and in the mFST/rFST, AC showed significant effect in mFST, MW showed significant effect in the rFST and XU showed significant effect in the mFST. CONCLUSION: In this study we have demonstrated the antidepressant activity of four South African medicinal plants in vitro and in vivo, supporting their rational use in traditional medicine.