Antiprotozoal Activity against Entamoeba histolytica of Plants Used in Northeast Mexican Traditional Medicine. Bioactive Compounds from Lippia graveolens and Ruta chalepensis

Abstract

Amoebiasis caused by Entamoeba histolytica is associated with high morbidity and mortality is becoming a major public health problem worldwide, especially in developing countries. Because of the side-effects and the resistance that pathogenic protozoa build against the standard antiparasitic drugs, e.g., metronidazole, much recent attention has been paid to plants used in traditional medicine around the world in order to find new antiprotozoal agents. We collected 32 plants used in Northeast Mexican traditional medicine and the methanolic extracts of these species were screened for antiprotozoal activity against E. histolytica trophozoites using in vitro tests. Only 18 extracts showed a significant inhibiting activity and among them six plant extracts showed more than 80% OPEN ACCESSMolecules 2014, 19 21045 growth inhibition against E. histolytica at a concentration of 150 µg/mL and the IC50 values of these extracts were determined. Lippia graveolens Kunth and Ruta chalepensis Pers. showed the more significant antiprotozoal activity (91.54% and 90.50% growth inhibition at a concentration of 150 µg/mL with IC50 values of 59.14 and 60.07 µg/mL, respectively). Bioassay-guided fractionation of the methanolic extracts from these two plants afforded carvacrol (1) and chalepensin (2), respectively, as bioactive compounds with antiprotozoal activity.

Trypanocidal Effects of Essential Oils from Selected Medicinal Plants. Synergy among the Main Components

“…Although the mechanism of antiprotozoal action of carvacrol is not well known, this compound showed good results in the growth inhibition of protozoa such as T. cruzi, T. brucei rhodesiense, Leishmania chagasi and Plasmodium falciparum. Furthermore, the methanolic extract of Lippia graveolens, containing carvacrol, inhibits the growth of Entamoeba histolytica [21]. It has been shown that β-pinene has antibacterial activity [22] and this monoterpene was present in various essential oils with leishmanicidal activity [23].…”

Antimicrobial effect of chalepensin against Streptococcus mutans

“…In addition, substances such as linoleic, linolenic, oleanolic, betulinic acids, betulin, and beta-sitosterol glucoside, among others, were reported to suppress adherence of S. mutans in-vitro (Wu, 2009). Chalepensin (Figure 1), previously isolated and identified (Quintanilla-Licea et al, 2014), can be found particularly in plants of the Rutaceae family (Günaydin and Savci, 2005), with reported anti-fertility (Kong et al, 1989), antitumor (Wu et al, 2003), and antiplatelet aggregation (Lv et al, 2015) activities. In the present study, we showed for the first time evidence of the in vitro antimicrobial effect of chalepensin, isolated from R. chalepensis, against S. mutans, which broadens its spectrum of biological activity and provides the basis for further validation in pre-clinical studies.…”

“…Chalepensin was extracted and identified as previously reported (Quintanilla-Licea et al, 2014). R. chalepensis pulverized leaves (600 g) were extracted during 40 h, using methanol in a Soxhlet equipment.…”

“…Next, the solvent was removed and the extract was dissolved in methanol, after which the solution was partitioned using n-hexane. This partition was chromatographed on silica gel and eluted with the consecutive gradients n-hexane-chloroform, chloroform-ethyl acetate, and methanol; 8 fractions were obtained, and fraction 2, containing a compound with an Rf of 0.41 was further fractioned using the gradients mentioned above (data not shown; Quintanilla-Licea et al, 2014). This process produced 5 fractions, of which fraction 2 contained a compound with that Rf, which was additionally fractioned with chloroform-ethyl acetate gradients, resulting in 4 main fractions; fraction 2 contained pure chalepensin (Figure 1), which was confirmed by mass spectroscopy and nuclear magnetic resonance (data not shown; Quintanilla-Licea et al, 2014).…”

Differential detection of Entamoeba species in stool samples collected from children in District Swat, Khyber Pakhtunkhwa Pakistan

“…Previous studies have shown that this infection is prevalent in Asia, Africa, South and Central America [12]. The poor hygienic conditions and environmental pollution have been shown to strengthen amoebic infections [13]. Mostly the amoebic cases are reported from developing countries and are introduced to developed countries due to the moments of human and animals [14].…”