Phedimus aizoon has been utilized as a medicinal plant in Asia. However, the production of phytochemical-rich extracts from P. aizoon and the evaluation of their bioactivity are limited. Herein, phytochemical-rich extracts were prepared by ultrasound-assisted extraction of P. aizoon, with a high extraction yield of 16.56%. The extracts contained about 126 mg of phenolics and 31 mg of flavonoids per g of the extracts. The chromatographic analysis (GC-MS and HPLC analyses) identified 19 notable phytochemicals of the extracts from P. aizoon, including pentacosane, hexadecanoic acid, gallic acid, vanillic acid, and quercetin. The gallic acid content of the extracts was relatively high at 2.75 mg/g. The identified compounds are known to have various bioactivities, such as antioxidant, antibacterial, and antifungal activities. In fact, the prepared extracts exhibited antioxidant activity at 24–28% of that of ascorbic acid. In addition, it showed antibacterial activity against both Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria). This study highlights that P. aizoon deserves attention as a natural bioactive substance and emphasizes the need for applications of the extracts from P. aizoon.

Sargassum horneri (SH) is a promising marine bioresource for producing bioactive compounds. Recently, the biological functions (including anti-inflammatory, antioxidant, and anticancer activities) of SH extracts have been revealed; however, efficient extraction processes to produce bioactive molecules (such as tannin and phenol) have not been carefully designed. In this study, the ultrasound-assisted extraction process was optimized based on the response surface methodology (RSM) to efficiently produce tannin and phenol from SH. Significant RSM models (p < 0.05) for predicting tannin and phenol yields were developed, and prethanol A concentration, temperature, and solid loading were significantly affected by tannin or phenol yield (p < 0.05). Following numerical optimization, the tannin and phenol yields achieved 14.59 and 13.83 mg/g biomass, respectively, under optimal conditions (39.1% solvent, 61.9 °C, 52.0 g/L solid loading, and 49.0% amplitude), similar to the model-predicted values (12.95 and 13.37 mg/g, respectively). Then, time profiling under optimal conditions determined the optimal time as 10.0 min, resulting in the highest yield (15.88 mg tannin and 14.55 mg phenol/g). The extracts showed antioxidant activity (IC₅₀: 79.86 μg/mL) comparable to that of ascorbic acid (vitamin C). It was found to be particularly non-toxic, raising its potential as a functional ingredient in food or cosmetics.

Plants of the genus Atraphaxis have been widely used as traditional herbal medicines and are just beginning to be recognized for their pharmacological activities by scientific validation. In particular, Atraphaxis virgata (Regel) Krasn. has not reported even fundamental data, such as antioxidant activity and phytochemical properties, which requires investigation for its medical application. In this study, phytochemical compounds of A. virgata extracts were identified using high-performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC-MS) and their antioxidant activity was evaluated. As a result, A. virgata extracts were analyzed using HPLC and found to contain hesperidin 13.18 mg/g-extract, rutin 4.49 mg/g-extract, catechin 3.23 mg/g-extract, gallic acid 2.93 mg/g-extract, epicatechin-3-gallate 1.28 mg/g-extract, kaempferol 0.26 mg/g-extract, and luteolin 0.09 mg/g-extract. Furthermore, GC-MS analysis detected nine compounds (e.g., lup-20(29)-en-3-one and decane) in the extracts, which were reported to have various biological activities. The ABTS IC₅₀, DPPH IC₅₀, and FRAP values of A. virgata extracts were determined to be 126.57 ± 0.24 μg/mL, 42.17 ± 1.14 μg/mL, and 122.59 ± 8.79 mmol/L, respectively. This study is the first to report the antioxidant activity of A. virgata, suggesting its potential as a functional food or medicinal material.

Sea buckthorn berries (SBB) are well known for being rich in natural bioactive compounds with high pharmacological activity. In this study, the optimization of extraction parameters was performed to recover phenolic compounds with high antioxidant activity from SBB. This study involved a systematic optimization approach, including screening for a variety of parameters, including temperature, time, ethanol concentration, agitation, and solid loading. On the basis of Plackett–Burman design (PBD) model, the two most significant parameters (agitation and solid loading) were selected, and the correlation model between those parameters and multiple responses was derived via response surface methodology (RSM). As a result, the optimal extraction condition for maximizing phenolic content and antioxidant activity was determined to be agitation at 109.54 rpm and a solid loading of 172.67 g/L. Under optimal conditions, SBB extract showed a total phenolic content of 0.21 mg/mL and ABTS and DPPH activities of 27.27% and 58.16%, respectively. The SBB extract prepared under optimal conditions was found to contain caffeic acid, vanillic acid, rutin, and vitamin B1 (thiamine). This work is the first challenge to design an optimization model for the efficient recovery of antioxidants from SBB and is significant in that the model can be applied simply and economically to conventional extraction processes.