Inhibitions of histamine release and prostaglandin E2 synthesis by mangosteen, a Thai medicinal plant

Medicinal properties of mangosteen (Garcinia mangostana)

Many tropical plants have interesting biological activities with potential therapeutic applications. Garcinia mangostana Linn. (GML) belongs to the family of Guttiferae and is named "the queen of fruits". It is cultivated in the tropical rainforest of some Southeast Asian nations like Indonesia, Malaysia, Sri Lanka, Philippines, and Thailand. People in these countries have used the pericarp (peel, rind, hull or ripe) of GML as a traditional medicine for the treatment of abdominal pain, diarrhea, dysentery, infected wound, suppuration, and chronic ulcer. Experimental studies have demonstrated that extracts of GML have antioxidant, antitumoral, antiallergic, anti-inflammatory, antibacterial, and antiviral activities. The pericarp of GML is a source of xanthones and other bioactive substances. Prenylated xanthones isolated from GML have been extensively studied; some members of these compounds possess antioxidant, antitumoral, antiallergic, anti-inflammatory, antibacterial, antifungal and antiviral properties. Xanthones have been isolated from pericarp, whole fruit, heartwood, and leaves. The most studied xanthones are alpha-, beta-, and gamma-mangostins, garcinone E, 8-deoxygartanin, and gartanin. The aim of this review is to summarize findings of beneficial properties of GML's extracts and xanthones isolated from this plant so far.

Ameliorative prospective of alpha-mangostin, a xanthone derivative from Garcinia mangostana against beta-adrenergic cathecolamine-induced myocardial toxicity and anomalous cardiac TNF-alpha and COX-2 expressions in rats

Altered membrane integrity and inflammation play a key role in cardiovascular damage. We investigated the salubrious effect of exogenously administered alpha-mangostin against beta-adrenergic cathecolamine-induced cardiovascular toxicity with special reference to membrane ATPases, lysosomal hydrolases and inflammatory mediators TNF-alpha and Cyclooxygenase-2 (COX-2) expressions in albino rats. Induction of rats with isoproterenol (150mg/kg body wt, i.p.) for 2 days resulted in a significant increase in the activities of serum and cardiac lysosomal hydrolases (beta-d-glucuronidase, beta-d-galactosidase, beta-d-N-acetylglucosaminidase, acid phosphatase and cathepsin-D). A significant increase in cardiac levels of sodium, calcium with a decrease in the level of potassium paralleled by abnormal activities of membrane-bound phosphatases (Na(+)-K(+) ATPase, Ca(2+) ATPase and Mg(2+) ATPase) were observed in the heart of ISO-administered rats. Cardiac TNF-alpha and COX-2 expressions were assessed by Western blotting. Cardiac TNF-alpha and COX-2 expressions were significantly elevated in ISO-intoxicated rats. Pre-co-treatment with alpha-mangostin (200mg/kg body wt.) orally for 8 days significantly attenuated these abnormalities and restored the levels to near normalcy when compared to ISO intoxicated group of rats. In conclusion, alpha-mangostin preserves the myocardial membrane integrity and extenuates anomalous TNF-alpha and COX-2 expressions by mitigating ISO-induced oxidative stress and cellular damage effectively. Restoration of cellular normalcy accredits the cytoprotective role of alpha-mangostin.

HPLC analysis of selected xanthones in mangosteen fruit

Xanthones are unique chemical compounds found in nature, composed of a tricyclic aromatic system with a variety of phenolic, methoxy, and isoprene substituents, giving rise to numerous derivatives. They dissolve to varying degrees in solvents ranging from alcohol to hexane. An optimum solvent mixture of acetone/water (80:20) selectively and effectively extracts a wide variety of xanthones. Subsequent HPLC analysis using standard C-18 RP and a 30-min gradient of 65-90% MetOH in 0.1% formic acid detects and separates numerous different xanthones with UV detection at 254 nm. The xanthones alpha-mangostin, 8-desoxygartanin, gartanin, beta-mangostin, 3-mangostin, and 9-hydroxycalabaxanthone have been extracted, identified, and quantitatively determined using this method. This analytical method is applied to the analysis of these xanthones in the rind of the mangosteen fruit, Garcinia mangostana.

Effects of Continuous Ingestion of Herbal Teas on Intestinal CYP3A in the Rat

Tenryocha, rooibos, and guava teas are widely consumed as herbal beverages, especially as a therapy against pollen allergy. To investigate the possible herbal tea-drug interaction the effect of continuous ingestion of these teas on cytochrome P450 (CYP) 3A were studied. Rats (n = 6) were allowed free access to either tea (experimental groups) or water (control) for two weeks. Midazolam (MDZ) (20 mg/kg) was orally administered and the serum concentration was determined. The area under the serum concentration-time curve (AUC(0-infinity)) and the maximum serum concentrations (C(max)) of MDZ were reduced by more than 60% after the treatment of tenryocha and rooibos tea (P<0.05). Intestinal MDZ 1'- and 4-hydroxylation activities mediated by CYP3A were increased in tenryocha and rooibos tea-treated group by 50% compared to the control group, although the results were not statistically significant. Furthermore, the Western blot analysis showed that CYP3A content was significantly increased in the intestine after the treatment of these teas (P<0.05). Hepatic MDZ hydroxylation and CYP3A content were slightly increased by these teas. The results suggested that two weeks ingestion of tenryocha and rooibos tea reduced serum concentration of MDZ by the induction of intestinal CYP3A. The possible interaction between tenryocha or rooibos tea and medicines mediated by CYP3A was suggested.

Quantitative and qualitative determination of six xanthones in Garcinia mangostana L. by LC-PDA and LC-ESI-MS

A new method was developed for the simultaneous analysis of six naturally occurring xanthones (3-isomangostin, 8-desoxygartanin, gartanin, alpha-mangostin, 9-hydroxycalabaxanthone and beta-mangostin). The quantitative determination was conducted by reversed phase high performance liquid chromatography with photodiode array detector (LC-PDA). Separation was performed on a Phenomenex Luna C18(2) (150 mm x 3.00 mm, 5 microm) column. The xanthones were identified by retention time, ultraviolet (UV) spectra and quantified by LC-PDA at 320 nm. The precision of the method was confirmed by the relative standard deviation (R.S.D.), which was < or =4.6%. The recovery was in the range from 96.58% to 113.45%. A good linear relationship was established in over two orders of magnitude range. The limits of detection (LOD) for six xanthone compounds were < or =0.248 microg/mL. The identity of the peaks was further confirmed by high performance liquid chromatography with time-of-flight mass spectrometry (LC-TOF MS) system coupled with electrospray ionization (ESI) interface. The developed methods were applied to the determination of six xanthones in Garcinia mangostana products. The satisfactory results showed that the methods are effective for the analysis of real samples.

Pharmacological Effects of Xanthones as Cardiovascular Protective Agents

Many epidemiological studies indicate that consumption of dietary polyphenolic compounds is beneficial in the prevention of cardiovascular diseases. Xanthones are a class of polyphenolic compounds that commonly occur in plants and have been shown to have extensive biological and pharmacological activities. Recently, the pharmacological properties of xanthones in the cardiovascular system have attracted great interest. Xanthones and xanthone derivatives have been shown to have beneficial effects on some cardiovascular diseases, including ischemic heart disease, atherosclerosis, hypertension and thrombosis. The protective effects of xanthones in the cardiovascular system may be due to their antioxidant, antiinflammatory, platelet aggregation inhibitory, antithrombotic and/or vasorelaxant activities. In particular, the antagonism of endogenous nitric oxide synthase inhibitors by xanthones may represent the basis for improved endothelial function and for reduction of events associated with atherosclerosis.

Antioxidative and neuroprotective activities of extracts from the fruit hull of mangosteen (Garcinia mangostana Linn.)

OBJECTIVE

The aim of this study was to investigate the antioxidative and neuroprotective activities of various extracts from the fruit hull of mangosteen (Garcinia mangostana Linn., GM).

MATERIALS AND METHODS

Four extracts: water, 50% ethanol, 95% ethanol and ethyl acetate, were used. The antioxidative activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging assay at extract concentrations of 1, 10, 50 and 100 microg/ml. Based on the free radical scavenging activity of the extracts, two (water and 50% ethanol) were selected for their protective activity in NG108-15 neuroblastoma cells against H(2)O(2)-induced oxidative stress and for cell viability using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

RESULTS

All extracts exhibited antioxidative activity. The water and 50% ethanol extracts showed high free-radical scavenging activity with IC(50) values of 34.98 +/- 2.24 and 30.76 +/- 1.66 microg/ml, respectively. Both water and 50% ethanol extracts exhibited neuroprotective activity on NG108-15 cells. The highest activity was observed at the concentration of 50 microg/ml for both the water and 50% ethanol extracts. For cytotoxicity test, none of the extracts was toxic to the cells except at the high concentration of 100 microg/ml.

CONCLUSIONS

These results suggest that the water and 50% ethanol extracts from the fruit hull of GM may be potent neuroprotectants.