Bio-Guided Fractionation of Retama raetam (Forssk.) Webb & Berthel Polar Extracts

Unveiling the phytochemical profile, antioxidant and antibacterial activities, acute toxicity insight and analgesic effect of Retama dasycarpa stems: An unexplored endemic plant from Morocco

Retama dasycarpa is an endemic shrubby leguminous plant of Morocco used in traditional folk medicine. The plant has never been studied for either its phytochemical or pharmacological properties. This study represents the first investigation of the phytochemical profile as well as the antioxidant, the antibacterial, the analgesic effects and the oral acute toxicity of Retama dasycarpa. Watery and hydromethanolic stems plant macerates have been investigated. Secondary metabolites quantitative analysis was achieved through spectrophotometric techniques. Antioxidant effect was explored through DPPH, ABTS and FRAP trials. Antibacterial activity was investigated using a micro-plates dilution assay. Analgesic activity was explored through acetic acid-induced writhing and tail-flick methods. Acute oral toxicity was investigated on mice. Phytochemical analysis was achieved through UHPLC connected to diode array and mass spectrometry detectors. The obtained results showed significant contents in total phenolics, flavonoids and tannins in both extracts especially the hydromethanolic extract whose contents were slighlty higher than the aqueous one resulting in a remarkable antioxidant activity. Compared to the aqueous extract, the H2O:MeOH (1:1) one showed notable antibacterial activity against the tested strains. The acute toxicity in mice revealed the non-toxicity of the extracts along with a promised starting material of central and peripheral analgesics. The UHPLC analysis revealed the presence of several bioactive phytochemicals pertaining to phenolic acids, flavonols, flavones and isoflavones. The obtained results demonstrate the richness of this endemic and unexplored plant in terms of bioactive compounds and their associated activities, making it a promising source of pharmacological ingredients.

Specialized Metabolites from the Allelopathic Plant Retama raetam as Potential Biopesticides

To cope with the rising food demand, modern agriculture practices are based on the indiscriminate use of agrochemicals. Although this strategy leads to a temporary solution, it also severely damages the environment, representing a risk to human health. A sustainable alternative to agrochemicals is the use of plant metabolites and plant-based pesticides, known to have minimal environmental impact compared to synthetic pesticides. Retama raetam is a shrub growing in Algeria’s desert areas, where it is commonly used in traditional medicine because of its antiseptic and antipyretic properties. Furthermore, its allelopathic features can be exploited to effectively control phytopathogens in the agricultural field. In this study, six compounds belonging to isoflavones and flavones subgroups have been isolated from the R. raetam dichloromethane extract and identified using spectroscopic and optical methods as alpinumisoflavone, hydroxyalpinumisoflavone, laburnetin, licoflavone C, retamasin B, and ephedroidin. Their antifungal activity was evaluated against the fungal phytopathogen Stemphylium vesicarium using a growth inhibition bioassay on PDA plates. Interestingly, the flavonoid laburnetin, the most active metabolite, displayed an inhibitory activity comparable to that exerted by the synthetic fungicide pentachloronitrobenzene, in a ten-fold lower concentration. The allelopathic activity of R. raetam metabolites against parasitic weeds was also investigated using two independent parasitic weed bioassays to discover potential activities on either suicidal stimulation or radicle growth inhibition of broomrapes. In this latter bioassay, ephedroidin strongly inhibited the growth of Orobanche cumana radicles and, therefore, can be proposed as a natural herbicide.

Graded Moisture Deficit Effect on Secondary Metabolites, Antioxidant, and Inhibitory Enzyme Activities in Leaf Extracts of Rosa damascena Mill. var. trigentipetala

Drought affects plant growth and yield in many agricultural areas worldwide by producing negative water potentials in the root zone that reduce water availability, affecting plant development and metabolism. This study investigated the effect of varying moisture regimes (100% field capacity (FC), well-watered plants, 50% FC (moderate water stress), and 25% FC (severe water stress)) on growth parameters, chlorophyll content, and bioactive molecule patterns, and the impact on antioxidant, lipoxygenase (LOX), and acetylcholinesterase (AChE) activities in Rosa damascena. The water deficit treatments reduced biomass production for both treatments (−29 and −33%, respectively, for MWS and SWS) and total chlorophyll (−18 and −38% respectively for MWS and SWS), relative to the control. The 50% FC treatment had the greatest effect on the phenolic profiles and their respective functionalities, with significant increases in the levels of total phenolic, benzoic (gallic, p-coumaric, and syringic acids) (+32%), and cinnamic (caffeic and trans-cinnamic acid) acids (+19%) and flavonoids (epicatechin-3-O-gallate) (+15%) compared to well-watered leaves (control leaves). The 50% FC treatment also exhibited the highest potential antioxidant activities (apart from NO-quenching activity), evidenced by the lowest IC50 and EC50 values. The inhibitory LOX and AChE capacities varied depending on the severity of stress, with superior activity in the 50% FC treatment. Overall, the drought tolerance in rose was associated mainly with its suitable manipulation of antioxidant production and orderly regulation of LOX and AChE activities.