Establishment of a quantitative and qualitative analysis and isolation method for tetracyclic iridoids from Morinda lucida Bentham leaves

In vitro fertilization using sperm activated by ML-2-3 isolated from Morinda lucida Bentham leaves

Purpose

ML-2-3 is a novel tetracyclic iridoid derived from Morinda lucida Bentham leaves. This compound has anti-trypanosomal and anti-leishmanial effects. In this study, the authors investigated effects of ML-2-3 on in vitro fertilization (IVF) rates, motility, and acrosome reaction of the mouse sperm.

Methods

IVF was performed using sperm from BALB/cByJJcl mice treated with ML-2-3. Computer-assisted sperm analysis (CASA) was performed on the sperm of C57BL/6J mice to investigate sperm motility. The effect of ML-2-3 on the acrosome reaction was examined by observing the fluorescence of sperm labeled with the acrosin-EGFP transgene.

Results

ML-2-3 improved IVF in BALB/cByJJcl mice with low fertilization rates. The optimum concentration of ML-2-3 in sperm pre-culture medium was 20 µM, and no significant toxicity of ML-2-3 was observed in developing embryos at this concentration. ML-2-3 affected sperm motility but not the acrosome reaction. ML-2-3 increased the IVF rate of mouse sperm that had been refrigerated for 3 days.

Conclusions

ML-2-3 can improve the outcome of IVF and motility without inducing the acrosome reaction in mice. These effects of ML-2-3 on sperm behaviors are different from those of the similar drugs.

Phenylpropanoid conjugated iridoids with anti-malarial activity from the leaves of Morinda morindoides

Two phenylpropanoid-conjugated iridoids, deglucosyl gaertneroside (1) and morindoidin (2), were isolated from the leaves of Morinda morindoides (Rubiaceae) by activity-guided fractionation using an anti-malarial activity assay. The known related iridoids molucidin (3) and prismatomerin (4), two lignans, abscisic acid, two megastigmanes, and two flavonol glycosides were also identified. The structures of isolated compounds were elucidated using spectroscopic analysis. The isolated compounds were evaluated for anti-malarial activity against the chloroquine/mefloquine-sensitive strains of Plasmodium falciparum together with cytotoxicity against adult mouse brain cells. Potent anti-malarial activity of 3 and 4 (IC₅₀ of 0.96 and 0.80 μM, CC₅₀ of 1.02 and 0.88 μM, and SI of 1.06 and 1.10, respectively) was shown, while new iridoids 1 and 2 and pinoresinol (5) displayed moderate activity (IC₅₀ of 40.9, 20.6, and 24.2 μM) without cytotoxicity (CC₅₀ > 50 μM). These results indicate that 1-5 may be promising lead compounds for anti-malarial drugs. In addition, our results imply the necessity of the quality control of the extract of M. morindoides leaves based on the contents of 1-5 in terms of the safety and efficacy.