Chemical composition, antioxidant activities and antibacterial activities of essential oil from Erythrina caffra Thunb. growing in South Africa

South African Medicinal Plants Traditionally Used for Wound Treatment: An Ethnobotanical Systematic Review

Microbial contamination of chronic wounds complicates their treatment. Traditional knowledge systems and the diversity of indigenous medicinal plants create a haven for traditional medicine practices in South Africa (SA). This systematic review aims to present a comprehensive ethnobotanical report of traditional medicines used in the documented empirical wound healing studies in SA. Google Scholar, PubMed, Medline EBSCOhost, Science Direct, and Scopus were sourced using the keywords/terminologies "South Africa", "medicinal plants", "traditional medicine" "indigenous", "skin", "wound", "ethnobotany", "survey", "interview", and "treatment" in different combinations. Relevant and unpublished records were retrieved from the Global Electronic Thesis Database. The searching process identified 32,419 records, of which 4005 studies were screened. Following the removal of 1795 duplicates, the remaining 2210 sources were screened by title and abstract, and 133 full-text reports were accessed and evaluated. Plants traditionally used for wound-healing purposes comprised 222 species belonging to 71 families, namely Asteraceae (predominantly the Helichrysum species), Asphodelaceae, Fabaceae, Solanaceae, and Euphorbiaceae. Plant organs used for medicinal remedies included leaves, roots, and bark prepared as poultices, infusions, decoctions, gel/ointments/lotions, and pastes. This review provides a valuable reference for future phytochemical and pharmacological studies and highlights the need for further ethnobotanical research to treat wounds in SA.

Review on antibacterial flavonoids from genus Erythrina: Structure-activity relationship and mode of action

The Fabaceae family, particularly genus Erythrina, is renowned for significant medicinal properties. These plants have been used as natural remedies to address various health issues and are rich in flavonoids. Therefore, this review aimed to provide a comprehensive overview of antibacterial activity, structure-activity relationship, especially against drug-resistance Staphylococcus aureus, and mode of action for flavonoids isolated from Erythrina. Data were collected from reputable electronic scholarly resources focusing on publications from 2000 to 2022. The results showed that the evaluated flavonoids include 31 % pterocarpans, 22 % flavanones, 20 % isoflavanones, 18 % isoflavones, 4 % isoflavans, 3 % isoflav-3-enes, 1 % 3-arylcoumarins, and 1 % coumestans. Most of these compounds in Erythrina plants were extracted from the roots and stem bark. Among these group of flavonoids, pterocarpan stands out as the most active class against S. aureus. Structure-activity relationship study emphasized pivotal contribution of the prenyl functional group to enhance antibacterial activity of flavonoids. Increasing the number of prenyl groups enhanced antibacterial effectiveness while modifying the group reduced this activity. The proposed antibacterial mechanisms of these flavonoids include the suppression of nucleic acid synthesis, disruption of cytoplasmic membrane function, and modulation of energy metabolism. Among the potent antibacterial flavonoids from genus Erythrina, compound 3,9-dihyroxy-10-γ,γ-dimethylallyl-6a,11a-dehydropterocarpan was found as the most potent against Methicillin-Resistant Staphylococcus aureus (MRSA) through the inhibition of nucleic acid synthesis. Other common flavonoids such as genistein, daidzein, apigenin, and luteolin exert antibacterial activity through the inhibition of ATP synthase.

Essential oils from Plumbago europaea L. aerial parts (leaves, flowers): GC-MS analyses and literature biological properties

Plumbago europaea L. belongs to the family Plumbaginaceae, which has many medicinal and nutritional applications. It is among the significant medicinal herbs used widely in folk medicine in Syria to treat skin diseases such as eczema and psoriasis. There are no previous studies of the aerial parts' essential oils of this plant. So, herein we report on determining the chemical composition of essential oils extracted from the aerial parts of P. europaea L., which were collected from a mountainous area in Latakia Province, Syria, by utilising the GC-MS technique. The major compounds identified in the flower's essential oils were: plumbagin (32.4%), hexadecanoic acid (13.79%), heneicosane (9.03%) and 2,6-di-tert-butyl-4-ethylphenol (8.40%). While in the leaves' essential oils were phytol (17.97%), dibutyl phthalate (15.45%), heneicosane (6.91%) and hexahydrofarnesyl acetone (6.72%). In addition, according to the published literature, most of the identified compounds have been reported to exhibit significant biological activities.

Antibacterial Activity of Hexanol Vapor In Vitro and on the Surface of Vegetables

Hexanol is a volatile alcohol and a major component of plant essential oils (EOs). However, the antibacterial activity of hexanol vapor has not been well studied. This study aimed to evaluate the antibacterial activity of hexanol. In this study, seven food-related bacteria were exposed to 1-, 2- or 3-hexanol vapor on agar media to evaluate their growth. Additionally, the total viable counts in three vegetables when exposed to 1-hexanol vapor were measured. The results showed that 1-hexanol exhibited antibacterial effects against Gram-negative bacteria but did not affect Gram-positive bacteria. However, compounds 2- and 3-hexanol did not show antimicrobial activity against any bacteria. For the vegetables, exposure to 1-hexanol vapor decreased the total viable bacterial counts in cabbage and carrot and inhibited bacterial growth in eggplants. In cabbage, 1-hexanol vapor at concentrations over 50 ppm decreased the total viable count within 72 h, and 25 ppm of vapor showed bacteriostatic activity for 168 h. However, 1-hexanol vapor also caused discoloration in cabbage. In summary, 1-hexanol has the potential to act as an antibacterial agent, but further studies are required for practical use. Moreover, the study results may help determine the antimicrobial activity of various EOs in the future.

Antioxidant Properties Mediate Nephroprotective and Hepatoprotective Activity of Essential Oil and Hydro-Alcoholic Extract of the High-Altitude Plant Skimmia anquetilia

There are many high-altitude plants such as Skimmia anquetilia that are unexplored for their possible medicinal values. The present study was conducted to examine the antioxidant activities of Skimmia anquetilia (SA) using in vitro and in vivo models. The SA hydro-alcoholic extracts were investigated using LC-MS for their chemical constituents. The essential oil and hydro-alcoholic extracts of SA were evaluated for pharmacological properties. The antioxidant properties were evaluated using in vitro DPPH, reducing power, cupric reducing antioxidant power, and metal chelating assays. The anti-hemolytic activity was carried out using a human blood sample. The in vivo antioxidant activities were evaluated using CCL₄-induced hepatotoxicity and nephrotoxicity assay. The in vivo evaluation included histopathological examination, tissue biochemical evaluation such as the kidney function test, catalase activity, reduced glutathione activity, and lipid peroxidation estimation. The phytochemical investigation showed that the hydro-alcoholic extract contains multiple important active constituents such as L-carnosine, acacetin, linoleic acid, leucylleucyl tyrosine, esculin sesquihydrate, etc., similar to the components of SA essential oil reported in a previous study. The high amount of total phenolic content (TPC) and total flavonoid content (TFC) reflect (p < 0.001) a high level of reducing power, cupric reducing, and metal chelating properties. This significantly (p < 0.001) inhibited enlargement of the liver, with a significant reduction in ALT (p < 0.01) and AST (p < 0.001). Highly significant improvement in the functioning of the kidney was noted using the blood urea and creatinine (p < 0.001) levels. Tissue-based activities showed a major rise in catalase, reduced glutathione, and reduced lipid peroxidation activities. We conclude from this study that the occurrence of a high quantity of flavonoid and phenolic contents had strong antioxidant properties, leading to hepatoprotective and nephroprotective activity. Further active constituent-specific activities should be evaluated.

Development of Chincho (Tagetes elliptica Sm.) Essential Oil Organogel Nanoparticles through Ionic Gelation and Process Optimization with Box-Behnken Design

The aim of this work was to obtain chitosan nanoparticles (<1000 nm) with chincho (Tagetes elliptica Sp.) essential oil (CEO-CSNPs) using the ionic gelation method. A Box−Behnken design (BBD) was applied, using chitosan solution (CS) pH (4.0, 4.4, 4.8); the mass ratio of CS/CEO (1:0.7, 1:0.85, 1:1.0) and the mass ratio of CS/CS-tripolyphosphate (1:0.46, 1:0.58, 1:0.7) as independent variables. The formulation-dependent variables, encapsulation efficiency (EE) and loading capacity (LC) of the CEO-CSNPs were evaluated. BBD determined that optimal conditions for CEO-CSNPs were pH: 4.4, CS/CEO mass ratio 1:0.7 and CS/TPP mass ratio 1:0.46. Once the optimization was defined, particle size (PS), zeta potential (ZP), polydispersity index (PDI), CEO-CSNPs morphological studies, in vitro CEO release, and antibacterial activity were determined. The CEO-CSNPs showed an EE of 52.64% and a LC of 11.56%, with a diameter of 458.5 nm, with a ZP of 23.30mV, and a PDI of 0.418. The SEM studies showed that the nanoparticles were rounded and had uniform shapes. In addition, CEO-CSNPs showed a minimum inhibitory concentration against Staphylococcus aureus, Salmonella infantis and Escherichia coli of 5.29, 10.57 and 10.57 µg/mL, respectively. These results could be very useful for the stabilization of chincho essential oil for food industry purposes. However, several studies about the release, as well as interaction with food matrices, will be necessary.

Natural alternatives for processed meat: Legislation, markets, consumers, opportunities and challenges

Consumers' interest in food with less and/or free from synthetic additives has increased considerably in recent years. In this context, researchers and industries have concentrated efforts on developing alternatives to these compounds. Replacing synthetic additives in meat products is a challenge, given their importance for sensory characteristics and food safety. Complementary technologies combined with the replacement and/or reduction of synthetic additives (hurdle technologies) has been studied focusing on the protection and extension of the shelf life of meat products. This review reports alternatives for replacing and/or reducing the use of synthetic additives in meat derivatives, aiming at the development of more natural and simpler meat products, familiar to consumers and considered clean labels.

A rapid analysis of antioxidants in Sanghuangporus baumii by online extraction-HPLC-ABTS

In the present study, a simple and efficient approach based on the online extraction-high performance liquid chromatography coupled with ABTS antioxidant assay (OLE-HPLC-ABTS) was established to quickly and directly analyze the antioxidants in S. baumii. Through this system, the HPLC mobile phase via a guard column packed with a S. baumii sample was used for online extraction (OLE). The separation was performed on an Agilent Poroshell EC-C18 column with a gradient elution using 0.1% formic acid (A) and 0.1% formic acid-acetonitrile (B) as mobile phase systems and detected at a wavelength of 254 nm. Then, the separated compounds were reacted with the antioxidant solution (ABTS), and the response was recorded at a wavelength of 400 nm. The developed analytical method was successfully applied to S. baumii samples, and eight antioxidants were identified. The established system integrated the online extraction, separation and online antioxidant detection, which is rapid, efficient, and suitable for the rapid screening of antioxidant compounds from solid sample mixtures.