Essential oil extraction, chemical analysis and anti-candida activity of calamintha nepeta (L.) Savi subsp. glandulosa (Req.) ball-new approaches

A comprehensive study on essential oils (EOs) extracted from different Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball (CG) samples from Tarquinia (Italy) is reported. In this study, the 24-hour steam distillation procedure for EO preparation, in terms of different harvesting and extraction times, was applied. The GC/MS analysis showed that CG essential oils from Tarquinia (TEOCG) belong to pulegone-rich chemotype. The analysis of 44 samples revealed that along pulegone (PUL) some other chemicals may participate in exerting the related antifungal activity. The results indicated that for higher activity, the EOs should be produced with at least 6 hours steam distillation process. Even it is not so dependent on the period of harvesting, however, it could be recommended not to harvest the plant in the fruiting stage, since no significant antifungal effect was shown. The maximum EO yield was obtained in August, with the highest PUL percentage. To obtain the oil with higher content of menthone (MEN), September and October should be considered as the optimal periods. Regarding to extraction duration, vegetative stage material gives the oil in the first 3 hours, while material from the reproductive phase should be extracted at least 6 or even 12 hours