Volatilome Analyses and In Vitro Antimicrobial Activity of the Essential Oils from Five South African Helichrysum Species

Abstract

Helichrysum genus was used in folk South African medicine to treat various human disorders. As a part of our on-going research addressing the exploitation of South African plants belonging to this genus, five species were investigated for their volatile and antimicrobial activities. The volatile organic compounds (VOCs) and the essential oils (EOs) were analysed by gas chromatography mass spectrometry (GC-MS). Microdilution was the method used for assessing both antimycotic and antibacterial activities, which was also tested by Kirby-Bauer agar disc diffusion. Total monoterpenes (TMs) dominated the VOCs of four species (H. trilineatum (70.6%), H. edwardsii (79.3%), H. cooperi (84.5%), and H. pandurifolium (57.0%)). H. cooperi and H. edwardsii EOs showed the predominance of TMs (68.2% and 84.5%, respectively), while H. pandurifolium and H. trilineatum EOs were characterized by the prevalence of TSs (86.5% and 43.6%, respectively). H. odoratissimum EO evidenced a similar amount of both TMs (49.5%) and TSs (46.4%). Microsporum canis was more sensitive to these EOs. The lowest minimum inhibitory concentration (MIC) was observed with H. pandurifolium and H. edwardsii EOs (0.25%). H. pandurifolium and H. trilineatum had a good effect on Staphylococcus aureus (MIC 5%). These findings open new perspectives for the exploitation of these natural compounds for application in cosmetics and pharmaceutics.

Use of Essential Oils in Veterinary Medicine to Combat Bacterial and Fungal Infections

“…Canine clinical isolates of S. aureus and S. pseudointermedius were shown to be quite sensitive also to Helichrysum pandurifolium , H. trilineatum , and H. araxinum [ 55 , 56 ].…”

“…Feline clinical isolates of M. canis and T. mentagrophytes were shown to be susceptible to H. pandurifolium EO (0.25% and 0.5%, respectively), to H . edwardsii (0.25% and 1%), and to H cooperi (0.5% and 1%), while H. odoratissimum , and H. trilineatum were less effective [ 55 ], and H. italicum and H. araxinum appeared quite uneffective [ 56 , 100 ].…”

“…The chemical composition was checked, revealing that H. pandurifolium was rich in viridiflor and contains beta pinene, spathulenol, delta cadinene, and epi-alfa-muurolol [ 123 , 124 , 125 , 126 ], which probably develop a synergistic action. The effectiveness of H. cooperi would be due to the presence of a good amount of terpinen-4-ol [ 127 ] and himachalol [ 128 ], while the richness in tujone of H. edwardsii could explain its ability in inhibiting dermatophytes [ 55 ].…”

Medicinal Properties and In Vitro Biological Activities of Selected Helichrysum Species from South Africa: A Review

“…Thus, these plants are potential reservoirs of bioactive compounds for drug discovery and development. Hitherto, only limited biological effects of the Helichrysum phytochemicals have been reported including, the antioxidant, antifungal, anti-inflammatory, anti-bacterial, hepatoprotective, anti-proliferative and anti-diabetic activities [ 7 , 11 , 12 , 13 ].…”

Antimicrobial Activity and Composition of Five Rosmarinus (Now Salvia spp. and Varieties) Essential Oils

“…), and Salvia granatensis B.T.Drew (synonym of Rosmarinus tomentosus Hub.-Mor. & Maire) [ 3 , 4 ]; only the first two species are widely used in traditional medicine [ 5 ] and as cooking ingredients [ 6 ].…”