Antioxidant activity of aryltetralone lignans and derivatives from Virola sebifera (Aubl.)

Lignans and Other Compounds From the Roots of Pandanus tonkinensis and Their Lipid Peroxidation Inhibitory Activity

A new phenylpropane (1) and 9 known (2-10) compounds were isolated from the methanol extract of Pandanus tonkinensis roots. Their chemical structures were determined as (7 S)-2,6-dimethoxyphenyl-7,9-propanediol-1 -O-β-D-glucopyranoside (1), isorhapontigenin (2), pinoresinol-4,4′-di -O-β-D-glucoside (3), isoeucommin A (4), pinoresinol-4′ -O-β-D-glucoside (5), acanthoside B (6), eucommin A (7), urolignoside (8), benzyl O-α-L-arabinopyranosyl-(1→6) -β-D-glucopyranoside (9), and (6 S,9 S)-roseoside (10) by comprehensive analysis of high-resolution electron spray ionization mass spectrum and nuclear magnetic resonance spectral data, as well as by comparison of their spectral data with those reported in the literature. In addition, the stereochemistry of 1 was successfully determined by both theoretical and calculated CD spectra. All the isolates were tested for their lipid peroxidation inhibitory effects by in vitro assay. Compounds 2-7 exhibited significantly lipid peroxidation inhibitory effects with IC50 values of 21.3 ± 1.7, 61.9 ± 3.9, 57.5 ± 5.5, 10.4 ± 0.7, 28.9 ± 0.3, 54.2 ± 3.5 µM, respectively, compared to that of the positive control, trolox (31.4 ± 2.2 µM).

Pharmacological Extracts and Molecules from Virola Species: Traditional Uses, Phytochemistry, and Biological Activity

Virola is the largest genus of Myristicaceae in America, comprising about 60 species of medium-sized trees geographically spread from Mexico to southern Brazil. The plant species of this genus have been widely used in folk medicine for the treatment of several ailments, such as rheumatic pain, bronchial asthma, tumors in the joints, intestinal worms, halitosis, ulcers, and multiple infections, due to their pharmacological activity. This review presents an updated and comprehensive summary of Virola species, particularly their ethnomedicinal uses, phytochemistry, and biological activity, to support the safe medicinal use of plant extracts and provide guidance for future research. The Virola spp.'s ethnopharmacology, including in the treatment of stomach pain and gastric ulcers, as well as antimicrobial and tryponosomicidal activities, is attributable to the presence of a myriad of phytoconstituents, such as flavonoids, tannins, phenolic acids, lignans, arylalkanones, and sitosterol. Hence, such species yield potential leads or molecular scaffolds for the development of new pharmaceutical formulations, encouraging the elucidation of not-yet-understood action mechanisms and ascertaining their safety for humans.

Amazonian Brazilian medicinal plants described by C.F.P. von Martius in the 19th century

ETHNOPHARMACOLOGICAL RELEVANCE

Information regarding the use of beneficial, native Brazilian plants was compiled by European naturalists during the 19th century. The German botanist C.F.P. von Martius was one of the most prominent naturalists and described the use of several Brazilian plants.

AIM OF THE STUDY

To present data on Amazonian medicinal plants documented by von Martius in his books.

MATERIALS AND METHODS

Data on Amazonian medicinal plants were obtained from three books published by von Martius. Traditional information about these plants was translated from Latin and the cited plant species reorganised according to current taxonomic criteria. Correlated pharmacological studies were obtained from different scientific databases.

RESULTS

A total of 92 native medicinal species from the Amazon were recorded in von Martius' books. These accounts described 117 different medical uses for these plants. Several parts of the plants were used, including many exudates. The principal use of the species recorded was the treatment of dermatological problems, followed by gastro-intestinal, urinary and respiratory disorders. Few species were recorded as purgatives and febrifuges, a result that differs from the observations of other naturalists. The efficacy of the recorded traditional uses has been confirmed for the few species that have been subjected to laboratory studies.

CONCLUSION

The data recorded by the German naturalist von Martius represent a rich, unexplored source of information about the traditional uses of Brazilian plants.

Chemoprotective effect of the tetrahydrofuran lignan grandisin in the in-vivo rodent micronucleus assay

Objectives

The chemoprotective effect of the tetrahydrofuran lignan grandisin against DNA damage induced by cyclophosphamide (200 mg/kg) has been evaluated using the in vitro rodent micronucleus assay.

Methods

The effects of a daily oral administration of grandisin (2, 4, or 8 mg/kg) for five days before exposure to cyclophosphamide on the frequency of micronucleus in the bone marrow of normal mice exposed and unexposed to cyclophosphamide were investigated (n = 5 per group). Electrochemical measurements were applied to investigate whether the antimutagenic effects of grandisin could be, at least in part, a consequence of its or its metabolite's antioxidant properties.

Key findings

Grandisin did not show mutagenic effects on the bone marrow cells of exposed mice. On the other hand, the oral administration of grandisin (2, 4, or 8 mg/kg) per day reduced dose-dependently the frequency of micronucleus, induced by cyclophosphamide, in all groups studied. Cyclic voltammograms showed two peaks for a grandisin metabolite, which were absent for grandisin.

Conclusions

Under the conditions tested herein, this study has shown that mice treated with grandisin presented, in a dose-dependent manner, a protective effect against cyclophosphamide-induced mutagenicity. This effect could be, at least in part, associated to grandisin bioactivation. These data open new perspectives for further investigation into the toxicology and applied pharmacology of grandisin.

Podophyllum hexandrum Offers Radioprotection by Modulating Free Radical Flux: Role of Aryl-Tetralin Lignans

We have evaluated the effect of variation in aryl-tetralin lignans on the radioprotective properties of Podophyllum hexandrum. Two fractionated fractions of P. hexandrum [methanolic (S1) and chloroform fractions (S2)], with varying aryl-tetralin lignan content were utilized for the present study. The peroxyl ion scavenging potentials of S1 and S2 were found to be comparable [i.e. 45.88% (S1) and 41% (S2)] after a 48 h interval in a time-dependent study, whereas in a 2 h study, S2 exhibited significant (P < 0.05) antioxidant activity in different metal ion + flux states. In the aqueous phase, S2 exhibited non-site-specific reactive oxygen species scavenging activity, i.e. 73.12% inhibition at 500 μg ml⁻¹. S1 exhibited 58.40 ± 0.8% inhibition (at 0.025 μg ml⁻¹) of the formation of reactive nitrite radicals, comparable to S2 (52.45 ± 0.825%), and also showed 45.01% site-specific activity (1000 μg ml⁻¹), along with significant (P < 0.05) electron donation potential (50–2000 μg ml⁻¹) compared to S2. Such activities of S1 could be attributed to the significantly (P < 0.05) higher levels of podophyllotoxin β-d-glucopyranoside (16.5 times) and demethyl podophyllotoxin glucoside (2.9 times) compared with S2. Together, these findings clearly prove that aryl-tetralin lignan content influences the radiation protective potential of the Podophyllum fractions to a great extent.