Spearmint (Mentha spicata L.) Phytochemical Profile: Impact of Pre/Post-Harvest Processing and Extractive Recovery

Exploring the Chemopreventive and Antioxidant Effects of Spearmint Leaf Hydroethanolic Extract in HPV16-transgenic Mice

BACKGROUND/AIM

Human papillomavirus (HPV) is the most common sexually transmitted infectious agent and, in cases of persistent infection, may cause cancer. This study evaluated the toxicological and antitumor properties of Mentha spicata extract (MSE) in KP14HPV16 mice, which carry HPV16 oncogenes.

MATERIALS AND METHODS

Thirty-three female FVB/n mice (Mus musculus), including 17 HPV-transgenic and 16 wild-type (WT) mice, were divided into six groups. The control groups received tap water (WT-C, n=5, and HPV-C, n=6), while the treatment groups received either 0.50 mg/ml MSE (WT-50 and HPV-50, n=6) or 0.55 mg/ml MSE (WT-55 and HPV-55, n=5) in drinking water for 28 days. Afterwards, animals were sacrificed, and blood and organs were collected for histopathological and biochemical analysis.

RESULTS

The main phenolic compounds in MSE were rosmarinic acid and luteolin-O-glucoronide. MSE did not significantly affect weight gain in WT mice; however, WT-55 gained significantly more weight than HPV-55. MSE demonstrated antioxidant activity as indicated by the modulation of hepatic superoxide dismutase and glutathione S-transferase (GST) activity, as well as renal GST activity, in MSE-treated HPV groups. MSE did not reduce histological lesion incidence or systemic inflammation in HPV16-transgenic mice.

CONCLUSION

In general, while MSE was safe and exhibited antioxidant activity, it did not significantly impact HPV16-induced lesions, warranting further research to assess systemic effects with different concentrations and durations.

Unveiling physiological responses and modulated accumulation patterns of specialized metabolites in Mentha rotundifolia acclimated to sub-tropical environment

Mints are aromatic plants of Lamiaceae, globally known for the phytochemical-rich essential oils. Most of the cultivated mints are menthol-rich, whereas spearmint being the only dominant carvone-rich species. In this study, another carvone-rich mint Mentha rotundifolia (L.) Huds., a native of temperate region was assessed for its acclimation in sub-tropical environment to see any possible changes in specialized metabolite accumulation. Plants grown under open environment was compared with glasshouse grown plants where, temperature, humidity and photoperiods were uniformly maintained. Thickened leaves with increased cuticular wax load (2.82 folds) and anthocyanin accumulation (202.97 µg/g) in the widened stems were observed in plants grown in open environment, while higher chlorophyll contents were exhibited by the glasshouse-grown plants. Enhanced antioxidant capacity in open environment, correlated with elevated concentration (86.4% increase for caffeic acid) of wall-bound phenolics was observed. Increased proline, hydrogen peroxide and malondialdehyde contents in open environment indicated the plant's ability to cope up with abiotic stress. Higher amounts of terpenes like (-)-carvone (2.68 folds) and D-limonene (1.35 folds) were found in both internal volatile pool and essential oil of glasshouse-grown plants. Histochemical study of glandular trichomes also supported this finding. In conclusion, glasshouse-grown plants showed relatively better growth and higher terpene contents, nevertheless the plant survived well in warmer environment, with increased antioxidant capacities and phenolic contents. Future study includes mass propagation of this species in different geographical locations with distinct climatic variations to determine the suitable sub-tropical locations for cultivation as a potential alternative to spearmint for commercial-scale (-)-carvone production.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01489-8.

Prediction of essential oil content in spearmint (Mentha spicata) via near-infrared hyperspectral imaging and chemometrics

Spearmint (Mentha spicata L.) is grown for its essential oil (EO), which find use in food, beverage, fragrance and other industries. The current study explores the ability of near infrared hyperspectral imaging (HSI) (935 to 1720 nm) to predict, in a rapid, nondestructive manner, the essential oil content of dried spearmint (0.2 to 2.6% EO). Spectral values of spearmint samples varied considerably with spatial coordinates, and so the use of averaging the spectral values of a surface scan was warranted. Data preprocessing was done with Multiplicative Scatter Correction (MSC) or Standard Normal Variate (SNV). Selection of spectral input variables was done with Least Absolute Shrinkage and Selection Operator (LASSO), Principal Component Analysis (PCA) or Partial Least Squares (PLS). Regression was executed with linear regression (LASSO, PLS regression, PCA regression), Support Vector Machine (SVM) regression, and Multilayer Perceptron (MLP). The best prediction of EO concentration was achieved with the combination of MSC or SNV preprocessing, PLS dimension reduction, and MLP regression (1 hidden layer with 6 nodes), achieving a good prediction with a ratio of performance to deviation (RPD) of 2.84 ± 0.07, an R² of prediction of 0.863 ± 0.008, and a RMSE of prediction of 0.219 ± 0.005% EO. These results show that NIR-HSI is a viable method for rapid, nondestructive analysis of EO concentration. Future work should explore the use of NIR in the visible spectrum, the use of HSI for determining EO in other plant materials and the potential of HSI to determine individual compounds in these solid plant/food matrices.

Towards Bioprospection of Commercial Materials of Mentha spicata L. Using a Combined Strategy of Metabolomics and Biological Activity Analyses

Spearmint (Mentha spicata L.) has been widely studied for its diversity of compounds for product generation. However, studies describing the chemical and biological characteristics of commercial spearmint materials from different origins are scarce. For this reason, this research aimed to bioprospecting spearmint from three origins: Colombia (Col), Mexico (Mex), and Egypt (Eg). We performed a biological activity analysis, such as FRAP, DPPH, and ABTS, inhibition potential of S. pyogenes, K. pneumoniae, E. coli, P. aeuroginosa, S. aureus, S aureus Methicillin-Resistant, and E. faecalis. Furthermore, we performed chemical assays, such as total polyphenol and rosmarinic acid, and untargeted metabolomics via HPLC-MS/MS. Finally, we developed a causality analysis to integrate biological activities with chemical analyses. We found significant differences between the samples for the total polyphenol and rosmarinic acid contents, FRAP, and inhibition analyses for Methicillin-Resistant S. aureus and E. faecalis. Also, clear metabolic differentiation was observed among the three commercial materials evaluated. These results allow us to propose data-driven uses for the three spearmint materials available in current markets.