Literature is limited regarding the potential use of the bark of Maclura pomifera as a source of bioactive compounds. The influence of different extraction methods was assessed for the chemical and biological properties of extracts obtained from the bark and periderm of M. pomifera. The extraction process was completed using three methods: microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and sonicator-assisted extraction (SAE). The extracts were characterized by total polyphenol content. The antioxidant capacity was evaluated using DPPH and ABTS methods, the antimicrobial effect was tested against Gram-positive and Gram-negative bacterial strains, and the inhibition of enzyme activity was conducted using α-glucosidase, lipase, and α-amylase assays. The extracts obtained from the periderm exhibited a lower total polyphenolic content compared to those obtained from the bark. The highest antioxidant activity using the DPPH method was observed in the MAE bark extracts and when using the ABTS method, and the highest activity was observed in the UAE bark extracts. Enzymatic activity was most strongly inhibited by the SAE bark extract. The most pronounced antibacterial potential was observed in the MAE and UAE bark extracts, with minimum inhibitory concentration values obtained below 1 mg/mL.
Pinus cembra L., also known as Swiss pine, is one of the lesser studied coniferous species, despite literature pointing out its great potential to be used for medical purposes due to its high contents in active phytochemicals. The aim of this study is to phytochemically assess rhytidome and periderm extracts obtained from Swiss pine from various locations and altitudes, so as to be able to deduce the best locations for harvesting samples with the highest biological activity. After the plant was analyzed histo-anatomically, hydroalcoholic extracts were obtained using ultrasounds, a rotary evaporator, and dry freezing. After determining the total polyphenolic content (TPC) in each sample, they were tested for antioxidant and enzymatic activity, while taking note of the influence of the varying altitudes and different harvesting regions on the intensity of each activity. The results from the TPC analysis show that rhytidome samples collected from the highest altitude (2429 m) displayed the highest content of polyphenols, with a general tendency for the amount of polyphenolic content to be directly correlated to altitude, this finding being further supported by the antioxidant activity also growing directly proportionally with the altitude. Enzymatic inhibition activity was found to be moderate for α-glucosidase and low for α-amylase. Following our findings, we can safely say that Pinus cembra L. extracts can be a great source of compounds with antioxidant activity; however, further studies are warranted to best determine the true potential of this species.