Antileishmanial Potential of Tropical Rainforest Plant Extracts

Abstract

A total of 115 different plant extracts from our collection, representing 96 plant species, have been evaluated for in vitro antileishmanial activity against L. amazonensis promastigotes. In addition, the extracts were screened for cytotoxic activity against BALB/c mouse macrophages in order to assess a selectivity index. Crude extracts that showed a selectivity index (CC50 for macrophage / IC50 for promastigotes) ≥ 5 or with IC50 < 12.5 μg/mL against promastigotes, a total of 28 extracts, were further screened for anti-amastigote activity. A total of 25 extracts showed promising activity against L. amazonensis promastigotes with low cytotoxic activity. Ten of these extracts showed selectivity indices, (CC50 for macrophages / IC50 for amastigotes) greater than 10 and are considered “hits”, worthy candidates for further phytochemical exploration: Conostegia xalapensis methanol bark extract, Endiandra palmerstonii bark extract, Eugenia monteverdensis acetone bark extract, Eugenia sp. “fine leaf” acetone bark extract, Exothea paniculata chloroform bark extract, Mallotus paniculatus ethanol bark extract, Matelea pseudobarbata ethanol extract, Quercus insignis ethanol bark extract, Sassafras albidum dichloromethane bark extract, and Stemmadenia donnell-smithii acetone bark extract.

Antileishmanial and cytotoxic potential of essential oils from medicinal plants in Northern Tunisia

“…The selectivity index (SI) is a parameter defining the balance between cytotoxicity and biological activity of the compound, corresponding to the highest active concentration with no toxicity and expressed as the ratio IC50 macrophage/IC50 parasite (Weninger et al, 2001). A SI value higher than 10 was considered effective for parasites and safe for macrophage (Camacho et al, 2008;Monzote et al, 2014).…”

Cytotoxic Norhopene Triterpenoids from the Bark of Exothea paniculata from Abaco Island, Bahamas

“…There are apparently no reported medicinal uses of this tree nor have there been any phytochemical investigations. In the course of our study on the biological activities of plants from Abaco Island, Bahamas [4][5][6], we have examined the crude bark extract of E. paniculata and found it to show considerable cytotoxicity. We had previously found the crude acetone bark extract of E. paniculata from Abaco Island to show selective in vitro cytotoxic activity to 5637 human bladder carcinoma cells, but little or no activity toward SK-Mel-28 (human melanoma), Hep-G2 (human hepatocellular carcinoma), or MDA-MB-231 (human mammary adenocarcinoma) cells [6].…”

Utilization of <i>Bridelia mollis</i> as herbal medicine, nutraceutical and functional food in southern Africa: A review

“…Traditional uses of B. mollis as herbal medicine encouraged researchers to evaluate antibacterial [33], antifungal [34,35], antileishmanial [14,36], antioxidative [13,37], antiplasmodial [38] and cytotoxicity [14,36,38]. Some of the documented biological activities may justify some of the medicinal uses of the species or may provide insight into the therapeutic potential of B. mollis.…”

“…Bridelia mollis methanol bark extract exhibited weak antileishmanial activity with IC 50 value > 200.0 µg/mL against Leishmania amazonensis promastigotes [36]. Bapela et al [14] [14].…”

“…Bridelia mollis methanol bark extract was not cytotoxic to BALB/c mouse macrophages with half maximal cytotoxic concentration (CC 50 ) value of > 200 μg/mL [36]. Bapela et al [38] assessed cytotoxicity activities of dichloromethane and methane root extracts of B. mollis against mammalian L-6 rat skeletal myoblast cells with podophyllotoxin as a control.…”