Micropropagation, phytochemistry and biological activity of the critically endangered Mammillaria herrerae Werdermann

This study intended to develop an efficient in vitro micropropagation technique for the critically endangered ornamental cactus Mammillaria herrerae Werdermaan and to assess the phytochemical profile, antioxidant, and enzyme inhibitory activities of callus and shoot cultures. The greatest shoot induction (99.2 ± 0.8%), with more multiple shoots (15.4 ± 2.1), and maximum shoot length (0.83 ± 0.12) were achieved on nutrient medium Murashige and Skoog (MS) with N6-furfuryladenine (6-KN, 2.5 µM) and 3-indolebutyric acid (IBA, 1.0 µM). The maximum frequency of callus induction (100%) and callus growth (5.37 ± 0.22 FW g/100 mL) were obtained on a nutrient medium MS with 1-phenyl-3-(1,2,3,-thiadiazol-5-yl)urea (TDZ, 10.0 µM) and 2-(1-naphthyl) acetic acid (NAA, 5.0 µM). The highest number of roots (8.1 ± 1.6) and maximum mean length of root (4.2 ± 0.5) and shoot (1.4 ± 0.2 cm) were observed on a rooting medium containing IBA (0.5 µM). The in vitro-developed M. herrerae plantlets were acclimatized in the greenhouse with 92% survival. Shoots containing a higher number of phytochemicals than callus cultures. Thirty-five compounds were found in shoot extract and twenty-six compounds in callus extract. Also, the total flavonoid content of shoot (0.96 mg RE/g extract) was higher than callus (0.41 mg RE/g extract). The shoot extracts displayed the best metal chelating and acetylcholinesterase inhibitory activities. The protocol developed for M. herrerae could be utilized for bioactive compounds production, ex situ conservation, and commercial clonal propagation of this rare ornamental cactus.