Boosting the essential oil yield from the rhizomes of cassumunar ginger by an eco-friendly solvent-free microwave extraction combined with central composite design

Natural food preservation with ginger essential oil: Biological properties and delivery systems

Recently, the increasing demand from consumers for preservative-free or naturally preserved foods has forced the food industry to turn to natural herbal and plant-derived preservatives rather than synthetic preservatives to produce safe foods. Essential oils derived from ginger (Zingiber officinale Roscoe) are widely known for their putative health-promoting bioactivities, and this paper covers their extraction methods, chemical composition, and antibacterial and antioxidant activities. Especially, the paper reviews their potential applications in food preservation, including nanoemulsions, emulsions, solid particle encapsulation, and biodegradable food packaging films/coatings. The conclusion drawn is that ginger essential oil can be used not only for direct food preservation but also encapsulated using various delivery forms such as nanoemulsions, Pickering emulsions, and solid particle encapsulation to improve its release control ability. The film of encapsulated ginger essential oil has been proven to be superior to traditional methods in preserving foods such as bread, meat, fish, and fruit.

Antiphotoaging properties of Zingiber montanum essential oil isolated by solvent-free microwave extraction against ultraviolet B-irradiated human dermal fibroblasts

Maintaining youthful skin from photoaging with natural products, including essential oils, is a vital strategy that has piqued the interest of researchers in the pharmaceutical and cosmetic industries. This research aimed to investigate the protective properties of Zingiber montanum (J. Koenig) Link ex A. Dietr. essential oil against ultraviolet B (UVB)-induced skin damage and photoaging in normal human dermal fibroblast (HDFn) cells. The essential oil was extracted from fresh plant rhizomes using solvent-free microwave extraction. Its antiphotoaging properties in HDFn cells were investigated using reactive oxygen species (ROS)-scavenging, wound healing, matrix metalloproteinases (MMP-1, MMP-3, and MMP-9) expression, procollagen synthesis, and elastase and tyrosinase inhibitory assays. The results showed that the test oil exhibited no significant toxicity in HDFn at concentrations up to 10 mg/mL, with cell viability exceeding 90%. Following UVB irradiation at 30 mJ/cm², Z. montanum oil demonstrated time and concentration-dependent ROS radical scavenging capabilities. In a cell migration assay, the essential oil demonstrated wound-healing properties. Z. montanum oil suppressed the expression of MMPs and enhanced the synthesis of type I procollagen at a concentration of 0.1-1 mg/mL. In addition, 0.1-1 mg/mL Z. montanum oil inhibited elastase activity in a concentration-dependent manner but did not affect tyrosinase activity. From these findings, the essential oil of Z. montanum could have potential applications in developing cosmeceutical products to prevent skin photoaging.

Repellent, larvicidal and adulticidal activities of essential oil from Dai medicinal plant Zingiber cassumunar against Aedes albopictus

Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito repellent. However, the compounds responsible for the repellent activity of the plant are still unknown. The aim of the study is to identify the components of Z. cassumunar essential oil that show repellent activity against Aedes albopictus. We also evaluated the larvicidal and adulticidal activities of Z. cassumunar essential oil against Ae. albopictus. In-cage mosquito repellent experiments showed that Z. cassumunar essential oil possessed moderate repellent activity with a minimum effective dose (MED) of 0.16 ± 0.01 mg/cm², compared to reference standard N,N-diethyl-3-methylbenzamide (DEET, 0.03 ± 0.01 mg/cm²). Bioassay-guided fractionation identified the major active compound of Z. cassumunar essential oil as (-)-terpinen-4-ol (1) (MED: 0.19 ± 0 mg/cm²). We also found that Z. cassumunar essential oil showed moderate larvicidal activity against first instar larvae of Ae. albopictus with a LC₅₀ (50% lethal concentration) of 44.9 μg/L after 24 h. Fumigation bioassays showed that Z. cassumunar essential oil exhibits moderate adulticidal activity against Ae. albopictus with a LC₅₀ of 5.44%, while (-)-terpinen-4-ol showed significant adulticidal activity with a LC₅₀ of 2.10% after 24 h. This study verifies that the Z. cassumunar essential oil has mosquito repellent activity, and that (-)-terpinen-4-ol is mainly responsible for this activity. Furthermore, this study provides scientific support for the folk usage of Z. cassumunar essential oil as mosquito repellent and indicates that Z. cassumunar essential oil and (-)-terpinen-4-ol can be used as plant-derived repellents and insecticides for mosquito control.

Optimization of Ultrasonic-Assisted Extraction and Purification of Rhein from Cassia fistula Pod Pulp

Rhein is used as an active ingredient in laxatives in medicinal herbal products and is a chemical marker for quality control purposes. Thus, a simple and effective method for the optimized extraction of a high amount of rhein from the fruit pulp of Cassia fistula was investigated using ultrasonic-assisted extraction (UAE). The response surface methodology was applied to find the most suitable parameters for optimizing the extraction process and to study the factors’ relationships with each other. The best conditions for ultrasonic extraction were the application of 1:40 g/mL solid-to-liquid ratio and 10% EtOH–H₂O as a solvent at 75 °C for 40 min. This method was compared to a conventional decoction in two variations. In these experiments, it was confirmed that the UAE was more favorable than the decoction methods. The resulting crude extract was further purified by liquid–liquid extraction with a basic pH adjustment, followed by recrystallization. High-purity rhein was obtained by using chromatographic techniques and nuclear magnetic resonance spectroscopy. Therefore, this study suggests that UAE is an efficient alternative method for the extraction of rhein from C. fistula pod pulp. The resulting optimized conditions can be applied as a useful tool for the large-scale industrial production of a rhein-rich plant extract.