The herbal extract ALS-L1023 from Melissa officinalis alleviates visceral obesity and insulin resistance in obese female C57BL/6J mice

Abstract Ethnopharmacological relevance Melissa officinalis L. (Labiatae; lemon balm) has traditionally been used as a medicinal herb to treat stress, anxiety, and insomnia. Current reports suggest that not only chronic stress stimulates angiogenesis, but angiogenesis also regulates adipogenesis and obesity. Because the herbal extract ALS-L1023 from Melissa officinalis inhibits angiogenesis, we hypothesized that ALS-L1023 could suppress visceral obesity and insulin resistance in obese female C57BL/6J mice, a mouse model of obese premenopausal women. Materials and methods The mice were grouped and fed for 16 weeks as follows: 1) low-fat diet (LFD), 2) high-fat diet (HFD), or 3) HFD supplemented with 0.4 or 0.8% ALS-L1023. Variables and determinants of visceral obesity, insulin resistance, and pancreatic dysfunction were then assessed via blood analysis, histology, immunohistochemistry, and real-time polymerase chain reaction. Results ALS-L1023 decreased weight gain, visceral adipocyte size, and serum lipid levels in HFD-fed obese mice. ALS-L1023 also normalized hyperglycemia and hyperinsulinemia and concomitantly reduced blood glucose levels during oral glucose tolerance tests. The pancreatic islet size and insulin-positive β-cell area were significantly reduced in ALS-L1023-treated mice compared with untreated obese controls, reaching a level similar to that of LFD-fed lean mice. ALS-L1023 suppressed pancreatic lipid accumulation, infiltration of inflammatory cells, and collagen levels. ALS-L1023 treatment altered the pancreatic expression of genes involved in steatosis, inflammation, and fibrosis. Conclusions Our findings indicate that the herbal extract ALS-L1023 from Melissa officinalis not only inhibits visceral obesity, but also attenuates the increased fasting blood glucose, impaired glucose tolerance, and pancreatic dysfunction seen in female obese mice. These results suggest that ALS-L1023 may be effective in the prevention of visceral obesity and insulin resistance in obese premenopausal women.