Ethnopharmacological Study of Garrya laurifolia and Its Antidiabetic Effect in Rats

This study aimed to scientifically validate the traditional use of Garrya laurifolia (Gl) leaves as an antidiabetic agent attributed to a community in Mexico. The descriptive ethnobotanical study was conducted in San Miguel Tecpan, a municipality of Jilotzingo, State of Mexico, Mexico, where a structured questionnaire was applied to 44 inhabitants. In vivo studies evaluated the acute oral toxicity of Gl leaves in murine and the effects of a leaf infusion on glycemia in normoglycemic and diabetic rats; in addition, the interaction between Gl and metformin (Met) was also evaluated. The in vitro antioxidant activity of Gl was determined. The phytochemical screening and quantification of phenolic and flavonoid content of Gl leaves were performed. Gl had a high relative frequency of citation (0.68) among respondents. Gl had a low acute toxicity risk with LD₅₀ > 5000 mg/kg. The extract had no hypoglycemic effect in normoglycemic rats, but it did have hypoglycemic and antihyperglycemic effects (250 and 500 mg/kg) in diabetic rats. The interaction between Gl (500 mg/kg) + Met (300 mg/kg) resulted in antidiabetic synergism. Gl showed strong antioxidant activity (93.1 ± 0.4%). Phytochemical screening revealed the presence of alkaloids, flavonoids, and some other phenolic compounds. The total phenol content was 77.9 ± 0.6 mg EQ/g and 87.7 ± 0.7 mg EAG/g, and the flavonoids content was 5.32 ± 0.2 mg EQ/g. UHPLC-MS/MS analysis identified chlorogenic acid, rutin, aucubin, luteolin 7-O-neohesperoside, and myricitrin. The findings support the potential use of Gl as a safe and effective antidiabetic agent.