Terminaliamide, a new ceramide and other phytoconstituents from the roots of Terminalia mantaly H. Perrier and their biological activities

Cladamide: a new ceramide from the endophytic fungus Cladosporium cladosporioides

A new ceramide, named cladamide (1), in addition to cinnamic acid (2), para-coumaric acid (3), stigmasterol-3-O-β-D-glucoside (4), and uracil (5), was isolated from the white beans culture of Cladosporium cladosporioides, a marine-derived endohpytic fungus isolated from the leaves of the mangrove, Avicennia marina (Forssk.) Vierh. Structure elucidation of compound 1 was established on the basis of extensive 1D and 2D NMR spectroscopic techniques in combination with HR-ESI-MS. The ability of the isolated compounds to inhibit acetylcholine esterase was evaluated. Compound 3 showed the highest acetylcholine esterase inhibitory activity (IC₅₀ = 0.057 ± 0.003 µM), followed by compound 4 (IC₅₀ = 0.068 ± 0.003 µM) and compound 1 (IC₅₀ = 0.099 ± 0.005 µM) compared to donepezil, the positive control, (IC₅₀ = 0.044 ± 0.002 µM). Compounds 2 and 5 showed lower activity (IC₅₀ = 0.182 ± 0.009 and 0.236 ± 0.012 µM, respectively). The results were further validated by molecular docking study.

Specific sub fractions from Terminalia mantaly (H. Perrier) extracts potently inhibit Plasmodium falciparum rings, merozoite egress and invasion

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia mantaly (H. Perrier) and Terminalia superba (Engl. & Diels) are sources of treatment for various diseases, including malaria and/or related symptoms in parts of Southwestern Cameroon. However, there is limited information on the extent of the antiplasmodial potential of their extracts.

AIM OF THE STUDY

The present study was designed to investigate the antiplasmodial potential of chromatographic sub fractions (SFs) from promising fractions of Terminalia mantaly (Tm) [Tmsb^wChl, the chloroform fraction from water extract of Tm, IC₅₀ (μg/mL) PfINDO: 0.56, Pf3D7: 1.12; SI > 357 (HEK/PfINDO) & 178 (HEK/Pf3D7)] and Terminalia superba (Ts) [Tsr^mEA, the ethyl acetate fraction from methanolic extract of Ts, IC₅₀ (μg/mL) PfINDO: 1.82, Pf3D7: 1.65; SI > 109 (HEK/PfINDO) & 121 (HEK/Pf3D7)] obtained from previous studies. The SFs were tested against Plasmodium falciparum 3D7 (Pf3D7-chloroquine sensitive) and INDO (PfINDO-chloroquine resistant) strains in culture. Also, the phytochemical profile of potent SFs was determined and finally, the inhibition of the asexual blood stages of Plasmodium falciparum by the SFs with the highest promise was assessed.

MATERIAL AND METHODS

Selected SFs were submitted to a second bio-guided fractionation using silica gel column chromatography. The partial phytochemical composition of potent antiplasmodial SFs was determined using gas chromatography coupled to mass spectrometry (GC-MS). The SYBR Green I-based fluorescence microtiter plate assay was used to monitor the growth of Plasmodium falciparum parasites in culture in the presence or absence of extracts. Microscopy and flow cytometry counting was used to assess the Plasmodium falciparum stage-specific inhibition and post-drug exposure growth suppression by highly potent extracts.

RESULTS

Twenty-one of the 39 SFs afforded from Tmsb^wChl showed activity (IC₅₀: 0.29-4.74 μg/mL) against both Pf3D7 and PfINDO strains. Of note, eight SFs namely, Tm25, Tm28-30, Tm34-36 and Tm38, exerted highly potent antiplasmodial activity (IC₅₀ < 1 μg/mL) with IC₅₀PfINDO: 0.41-0.84 μg/mL and IC₅₀Pf3D7: 0.29-0.68 μg/mL. They also displayed very high selectivity (50 < SI_PfINDO, SI_Pf3D7 > 344) on the two Plasmodial strains. On the other hand, 7 SFs (SFs Ts03, Ts04, Ts06, Ts09, Ts10, Ts12 and Ts13) from Tsr^mEA showed promising inhibitory potential against both parasite strains (IC₅₀: 2.01-5.14 μg/mL). Sub fraction Tm36 (IC₅₀PfINDO: 0.41 μg/mL, SI_PfINDO > 243; IC₅₀Pf3D7: 0.29 μg/mL, SI_Pf3D7 > 344) showed the highest promise. The GC-MS analysis of the 8 selected SFs led to the identification of 99 phytometabolites, with D-limonene (2), benzaldehyde (12), carvone (13), caryophyllene (35), hexadecanoic acid, methyl ester (74) and 9-octadecenoic acid, methyl ester (82) being the main constituents. Sub fractions Tm28, Tm29, Tm30, Tm36 and Tm38 inhibited all the three intraerythrocytic stages of P. falciparum, with strong potency against ring stage development, merozoite egress and invasion processes.

CONCLUSIONS

This study has identified highly potent antiplasmodial SFs from Terminalia mantaly with significant activity on the intraerythrocytic development of Plasmodium falciparum. These SFs qualify as promising sources of novel antiplasmodial lead compounds. Further purification and characterization studies are expected to unravel molecular targets in rings and merozoites.

Plants of the Genus Terminalia: An Insight on Its Biological Potentials, Pre-Clinical and Clinical Studies

The evaluation and confirmation of healing properties of several plant species of genus Terminalia based on their traditional uses and the clinical claims are of utmost importance. Genus Terminalia has received more attention to assess and validate the therapeutic potential and clinical approval due to its immense folk medicinal and traditional applications. Various species of Terminalia genus are used in the form of herbal medicine and formulations, in treatment of diseases, including headache, fever, pneumonia, flu, geriatric, cancer, to improve memory, abdominal and back pain, cough and cold, conjunctivitis, diarrhea, heart disorder, leprosy, sexually transmitted diseases, and urinary tract disorders. These are reported to possess numerous biological properties, counting: antibacterial, antifungal, antiinflammatory, antiviral, antiretroviral, antioxidant, and antipa7rasitic. This current research review aims to update the detailed biological activities, pre-clinical and clinical studies of various extracts and secondary metabolites from several plant species under the genus Terminalia, along with information on the traditional uses and chemical composition to develop a promising strategy for their potential applications in the form of medicine or use in modern drug formulations for treating diseases like pneumonia, flu, and other types of viral infections or controlling human contagions.