Context: In Iran, conventional production methods of herbal oils are widely used by local practitioners. Administration of oils is rooted in traditional knowledge with a history of more than 3000 years. Scientific evaluation of these historical documents can be valuable for finding new potential use in current medicine. Objective: The current study (i) compiled an inventory of herbal oils used in ancient and medieval Persia and (ii) compared the preparation methods and therapeutic applications of ancient times to current findings of medicinal properties in the same plant species. Materials and methods: Information on oils, preparation methods and related clinical administration was obtained from ancient Persian documents and selected manuscripts describing traditional Persian medicine. Moreover, we investigated the efficacy of medicinal plant species used for herbal oils through a search of the PubMed, Scopus and Google Scholar databases. Results: In Iran, the application of medicinal oils date back to ancient times. In medieval Persian documents, 51 medicinal oils produced from 31 plant species, along with specific preparation methods, were identified. Flowers, fruits and leaves were most often used. Herbal oils have been traditionally administered via oral, topical and nasal routes for gastrointestinal, musculoskeletal, and neural diseases, respectively. According to current investigations, most of the cited medicinal plant species were used for their anti-inflammatory and analgesic properties. Conclusions: Medicinal oils are currently available in Iranian medicinal plant markets and are prepared using traditional procedures for desirable clinical outcomes. Other than historical clarification, the present study provides data on clinical applications of the oils that should lead to future opportunities to investigate their potential medicinal use.

Pharmacognostic evaluation of medicinal plants may assess their current applications and possibly results in finding new active components. In this study, ash and extractive values and high performance thin layer chromatography fingerprints of Alyssum homolocarpum (Brassicaceae) seed extracts were investigated to elucidate its composition. Differential scanning calorimetry and gas chromatography-mass spectrometry analysis were employed to determine the components of A. homolocarpum seed oil (AHO). Neurosphere assay, in vitro differentiation and immunofluorescence analysis were performed to evaluate the effects of oral administration of AHO (0.5 or 1 g/kg/day for 14 days) on proliferation and differentiation of neural stem cells (NSCs) in adult male BALB/c mice. Total, acid-insoluble and water-soluble ash values were determined as 45.83 ± 5.85, 6.67 ± 2.89 and 28.33 ± 2.89 mg/g, respectively. The extractive values were 4.90, 0.43 and 0.56 % (w/w) for n-hexane, dichloromethane and ethanolic extracts, respectively. Interestingly, AHO was mainly composed of α-linolenic acid (89.71 %), β-sitosterol (3.3 mg/g) and campesterol (0.86 mg/g). Administration of AHO at 1 g/kg/day significantly increased proliferation of NSCs, as evidenced by an increase in mean neurosphere-forming frequency per brain (872.7 ± 15.17) and neurosphere diameter (101 ± 2.48 µm) compared to the control group (424.3 ± 59.29 and 78.63 ± 1.7 µm, respectively; P < 0.05). AHO treatment did not affect in vitro differentiation of the harvested NSCs. Our data show that A. homolocarpum seed oil is a rich source of α-linolenic acid and β-sitosterol with potential therapeutic application to enhance NSC proliferation and recruitment in neurological diseases.

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