Dr. Sergio Martínez PUBLICACIONES

BMC Chem. 2019;13(1):22

α‑Glucosidase inhibitors from a mangroveassociated fungus,

Zasmidium sp. strain EM5‑10

Dioxelis Lopéz, Lilia Cherigo, Luis C. Mejia, Marco A. Loza‑Mejía, Sergio Martínez‑Luis.


Background: Mangroves plants and their endophytes represent a natural source of novel and bioactive compounds.

In our ongoing research on mangrove endophytes from the Panamanian Pacific Coast, we have identified several bioactive

endophytic fungi. From these organisms, an isolate belonging to the genus Zasmidium (Mycosphaerellaceae) showed 91.3% of inhibition against α-glucosidase enzyme in vitro.

Results: Zasmidium sp. strain EM5-10 was isolated from mature leaves of Laguncularia racemosa, and its crude extract showed good inhibition against α-glucosidase enzyme (91.3% of inhibition). Bioassay-guided fractionation of the crude extract led to obtaining two active fractions: L (tripalmitin) and M (Fungal Tryglicerides Mixture). Tripalmitin (3.75 μM) showed better inhibitory activity than acarbose (positive control, IC50 217.71 μM). Kinetic analysis established that tripalmitin acted as a mixed inhibitor. Molecular docking and molecular dynamics simulations predicted

that tripalmitin binds at the same site as acarbose and also to an allosteric site in the human intestinal α-glucosidase (PDB: 3TOP).

Conclusions: Zasmidium sp. strain EM5-10 represents a new source of bioactive substances that could possess beneficial

properties for human health.




Natural Product Communications 2019; 14 (1), 31-32

Antiparasitic Compounds from the Panamanian Marine Bacterium Pseudomonas aeruginosa

Sergio Martínez-Luis, Lilia Cherigo, Carmenza Spadafora, Marcelino Gutiérrez.


Fractionation of the ethyl acetate extract of the bacterium Pseudomonas aeruginosa led to the isolation of five compounds, cyclo–(L-Phe-L-Pro) (1), 3-heptyl- 3-hydroxy-1,2,3,4-tetrahydroquinoline-2.4-dione (2), 2-heptyl-4-hydroxyquinoline (3), 2-nonyl-4-hydroxyquinoline (4), and 1-phenazinecarboxylic acid (5).

The structures of compounds 1−5 were established by spectroscopic analyses. Compounds 2−4 produced inhibition on the growth of Plasmodium falciparum, with IC50 values of 3.47, 2.57 and 2.79 μg/mL, respectively. Compounds 3−4 had activity against Trypanosoma cruzi, with IC50 values of 3.66 and 3.99 μg/mL. Finally, all compounds were found inactive when tested against Leishmania donovani at 10 μg/mL.




SCIENTIFIC REPORTS | (2018) 8:13629

Identification of Major α-Glucosidase Inhibitors from Stem Bark of Panamanian Mangrove Plant Pelliciera rhizophorae

Lilia Cherigo, Sergio Martínez-Luis.


In our continuous search for α-glucosidase inhibitors, three active pentacyclic triterpenes were isolated from stem bark samples of the Panamanian mangrove Pelliciera rhizophorae Triana & Planchon. These compounds were identified by both spectroscopic and spectrometric analysis. Of the isolated compounds, only betulinic acid has been previously isolated from P. rhizophorae leaves while both betulin (IC50 2.09 μM) and lupeol (IC50 0.58 μM) were isolated from this plant for the first time. All three pentacyclic triterpenes inhibited the α‑glucosidase enzyme in a concentration‑dependent manner, and their inhibitory activity was higher than that of the antidiabetic drug acarbose (IC50 241.6 μM). Kinetic analysis established that betulin and lupeol acted as competitive

inhibitors. Finally, docking analysis suggested that all three triterpenes bind at the same site as acarbose does in the human intestinal α‑glucosidase (PDB: 3TOP). This work contributes further evidence similar to previous studies that point out that the aerial parts of P. rhizophorae might be potential agents in controlling hyperglycemia in diabetic persons.





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