Evaluation of in vivo Genotoxicity of Plant Flavonoids, Quercetin and Isoquercetin

Quercetin inhibits body weight gain and adipogenesis via matrix metalloproteinases in mice fed a high-fat diet

BACKGROUND/OBJECTIVES

Limited studies reported that quercetin inhibited adipogenesis and neovascularization by inhibiting matrix metalloproteinases (MMPs) activity, but such mechanisms have not been elucidated in animal experiments. In this study, we investigated the inhibitory effects of quercetin on weight gain and adipose tissue growth through the regulation of mRNA expressions of adipogenic transcription factors and MMPs in mice fed a high-fat diet (HFD).

MATERIALS/METHODS

Five-wk-old C57BL/6J mice were fed a normal diet (ND), HFD, HFD containing 0.05% of quercetin (HFQ0.05), or HFD containing 0.15% of quercetin (HFQ0.15) for 16 wks. Glycerol-3-phosphate dehydrogenase (GPDH) activity was measured using a commercial kit. The mRNA expressions of transcription factors related to adipocyte differentiation were determined by real-time polymerase chain reaction (PCR). The mRNA expressions of MMPs and concentrations of MMPs were measured by real-time PCR and enzyme-linked immunosorbent assay kit, respectively.

RESULTS

Quercetin intake reduced body weight gain and epididymal adipose tissue weights (P < 0.05). GPDH activity was higher in the HFD group than in the ND group but lower in the quercetin groups (P < 0.05). The mRNA expressions of CCAAT/enhancer binding protein β (C/EBPβ), C/EBPα, peroxisome proliferator-activated receptor γ, and fatty acid-binding protein 4 were lower in the quercetin groups than in the HFD group (P < 0.05). Similarly, the mRNA expression and concentrations of MMP-2 and MMP-9 were significantly lower in the quercetin groups than in the HFD group (P < 0.05).

CONCLUSION

The study confirms that quercetin suppresses body weight gain and adipogenesis by inhibiting transcription factors related to adipocyte differentiation and MMPs (MMP-2 and MMP-9), in mice fed a HFD.

Aqueous extract from leaves of Doliocarpus dentatus (Aubl.) Standl. relieves pain without genotoxicity activity

ETHNOPHARMACOLOGICAL RELEVANCE

In the State of Mato Grosso do Sul, the watery sap of Doliocarpus dentatus is used to alleviate thirst, and the leaves of this species are used to relieve pain and swelling associated with inflammatory processes.

AIM OF THE STUDY

This study aimed to analyze the compounds of the leaves from the aqueous extract of D. dentatus (EADd) and evaluate its toxicogenetic and pain relief effects in animal models.

MATERIALS AND METHODS

Compounds were identified in EADd by UHPLC-HRMS (Ultra high-performance liquid chromatography coupled to high resolution mass spectrometry). The oral dose of 17 mg/kg EADd, calculated according to ethnopharmacological uses, and doses between 30 and 300 mg/kg were used to test Swiss mice in formalin- and acetic acid-induced models of pain and behavior. EADd (100-2000 mg/kg) was assayed in mice by comet, micronucleus, and phagocytosis tests and by peripheral leukocyte counts.

RESULTS

Phenolic compounds and flavonoids as well as trigonelline and isoquercetin were identified in EADd. All oral doses of EADd exhibited antinociceptive activity, as indicated by a decrease in pain in both phases, a decrease in cold hypersensitivity induced by formalin, and a decrease in abdominal contortions induced by acetic acid. EADd did not alter the exploratory, motor or motivational activities of the animals. The comet and micronucleus tests indicated that EADd was not genotoxic and did not change the phagocytic activity or peripheral leukocyte count.

CONCLUSIONS

These results demonstrate that EADd could act as an antinociceptive agent that does not present genotoxicity. This study should contribute to justifying, in part, the popular use of D. dentatus in pain management, ensuring its safe use.