Phytochemical analyses and biological activities of selected medicinal plant extracts: bioactive nutrition and pharmaceutical resources.

Abstract

This study was initiated to conduct an ethnobotanical survey among herbalists in the Wilaya of Relizane, Algeria, highlighting the cultural and therapeutic significance of two major medicinal plants: Ptychotis verticillata Duby and Thymus vulgaris L. These species, widely used in local phytotherapy, were subjected to a detailed analysis of their essential oils extracted by hydrodistillation to evaluate their in vitro biological activities, supported by molecular docking studies and pharmacokinetic and toxicological (ADMET) predictions. The hydrodistillation process yielded 1.2% (w/w) and 1.5% (w/w) essential oils from Ptychotis verticillata Duby and Thymus vulgaris L., respectively. Gas chromatography-mass spectrometry (GC-MS) analyses confirmed the chemical complexity and richness of these mixtures, identifying thymol as the predominant compound at 38.4% in T. vulgaris and carvacrol at 29.7% in P. verticillata, along with other monoterpenes. Biological assays demonstrated significant antioxidant activity via DPPH radical scavenging, with IC50 values of 45.3 ± 2.1 μg/mL for P. verticillata and 38.7 ± 1.8 μg/mL for T. vulgaris, compared to ascorbic acid (IC50 = 12.4 ± 0.9 μg/mL). Notable anti-inflammatory effects were evidenced by erythrocyte membrane stabilization and inhibition of protein denaturation, with inhibition rates of 65.2 ± 4.3% and 69.8 ± 3.7%, and 61.5 ± 2.9% and 67.3 ± 3.1%, respectively, at 100 μg/mL. The essential oils also exhibited effective insecticidal activity against Aphis spiraecola, inducing 78% mortality at 0.5% after 24 hours. Regarding antimicrobial efficacy, these oils exhibited marked inhibition against pathogenic strains, including Escherichia coli, methicillinsensitive and resistant Staphylococcus aureus, and Enterococcus faecalis, producing inhibition zones of 18.5 ± 0.7 mm, 20.3 ± 0.9 mm, 15.9 ± 1.0 mm, and 19.1 ± 0.8 mm, respectively. Synergistic interaction between the essential oils of Ptychotis verticillata Duby and Thymus vulgaris L. enhanced their potential as natural antimicrobial agents, in some cases outperforming certain conventional antibiotics. Molecular docking analyses of three bacterial target enzymes revealed promising binding affinities of -7.6 to -9.1 kcal/mol for the major identified compounds, suggesting relevant competitive inhibition mechanisms. In silico studies of pharmacokinetic and toxicological properties predicted high intestinal absorption (>85%), moderate blood-brain barrier permeability, low acute toxicity (LD50 > 2000 mg/kg), and a moderate risk of skin sensitization for some molecules. Nutritional analysis of the plants revealed a balanced composition, characterized by high total carbohydrate content, moderate protein levels, low lipid content, and a slightly acidic pH, supporting their traditional use in phytotherapy and as potential nutritional supplements. Based on these data, a topical pharmaceutical formulation named "Derma Phyto Calm" was developed, incorporating essential oils of Ptychotis verticillata Duby and Thymus vulgaris L. enriched with natural vitamin E to enhance antioxidant stability. This natural product aims to exploit the oils' antimicrobial and anti-inflammatory properties, offering a promising phytotherapeutic alternative for treating inflammatory and infectious skin conditions, including intimate areas. Furthermore, given their low toxicity, these plants could also be used in infusion form as an accessible nutritional supplement for sensitive populations. This research exemplifies a rigorous integration of traditional knowledge with contemporary scientific methodology, encouraging the sustainable exploitation of Algerian medicinal plant resources and emphasizing ongoing biomedical research to valorize their therapeutic potential fully.