Phytochemical and biological activities of some Iranian medicinal plants

CONTEXT

Due to adverse effects of synthetic compounds, there is a growing interest in utilization of plant-derived natural products in the pharmaceutical and food industries. Iranian endemic medicinal plants widely used in traditional practice have attracted much attention as antibacterial and antioxidant agents.

OBJECTIVE

This review attempts to compile the accessible scientific research pertained to phytochemical compounds, antibacterial and antioxidant effects of essential oils obtained from some of the most widely used and distributed medicinal plants in Iran.

METHODS

This review has been compiled using references via reliable databases (Google Scholar, SID and Science Direct) from 2010 to 2020. This literature review was limited to references published in English and Persian languages.

RESULTS

Based on studies heretofore carried out, essential oils isolated from mentioned medicinal plants exhibited strong antioxidant activity which is attributed to their main phytochemical compounds; thymol, carvacrol, p-cymene and γ-terpinene. In addition, the antibacterial activities of essential oils of most plant species from Apiaceae and Asteraceae families were more susceptible against Gram-positive bacteria; Staphylococcus aureus and Bacillus cereus than Gram-negative bacteria; however, essential oils of other studied plant species manifested similar behaviours against both Gram-positive and -negative bacteria.

CONCLUSIONS

As there is rich ethnobotanical knowledge behind Iranian endemic medicinal plants, further scientific research is required to prove their safety and efficacy. This review revealed that there are numerous valuable medicinal plants adoptable in food and pharmaceutical industries in the near future.

Diversity and Distribution Patterns of Endemic Medicinal and Aromatic Plants of Iran: Implications for Conservation and Habitat Management

Iran, with its unique climatic and topographic conditions, is home to about 8200 species of vascular plants. Approximately 2300 of the 8200 species are popularly characterized as medicinal or aromatic. Here, we compile information about the endemic medicinal and aromatic plants (MAPs) of Iran and map their distributions. Our survey found 180 endemic species of MAPs, belonging to 10 families and 30 genera. The majority of species are found in Lamiaceae, Fabaceae, and Apiaceae, with 86, 30, and 18 species, respectively. Approximately 70% of these plants have been recorded in the 10 provinces of Esfahan, Kerman, Fars, Tehran, Chaharmahal va Bakhtiari, East Azarbaijan, Lorestan, West Azarbaijan, Hamadan, and Mazandaran. These provinces are located in the Iran-o-Turanian region, one of the three major phytogeographic regions in Iran, which covers five areas of endemism (i.e., Azarbaijan, Zagros, Kopet Dagh-Khorassan, Alborz, and Central Alborz). So, Iran-o-Turanian region is the main center of diversity for the Iranian endemic MAPs. The north, center and western parts of Iran are rich in MAPs and could be considered as the dominant biodiversity hotspots of Iran more seemingly due to the diverse climatic and geographic assortment which generates the highest frequency and distribution of MAPs. Many of these MAPs are at the edge of extinction due to the unwise, unscientific harvesting and/or global climate change. Therefore, there is an urgent need to conserve and propagate some of these important MAPs to save them from extinction and also to ensure the availability of raw materials for their use and future research into their efficacy. Furthermore, identifying the areas of endemism (AEs) is an essential part of ongoing regional conservation management programs in Iran and worldwide.

Chemical Variability in the Composition of Zhumeria majdae (Rech. F. & Wendelbo) Essential Oil According to Storage Time and Temperature

Zhumeria majdae (Rech. F. & Wendelbo) is an aromatic herb belonging to the Lamiaceae family, traditionally employed in the Persian medicine for the treatment of a wide number of diseases. In the present study, the chemical composition of Z. majdae essential oil obtained from the plant’s aerial features, and stored at various temperatures (refrigerator temperature 4 °C, freezer temperature −20 °C, and room temperature 20 ± 3 °C) and times (0, 3, 6, and 9 months) was studied. The essential oil was isolated through hydrodistillation, and its composition was evaluated by gas chromatography/mass spectrometry (GC/MS). The results showed that the composition of essential oils changed as a function of the various storage temperatures and times. Linalool (34.85–48.45%), camphor (27.09–39.17%), limonene (1.97–4.88%), and camphene (1.6–4.84%) made up the main volatile compounds which showed differences in their concentrations according to the various storage conditions. Notably, when compared to a non-stored treatment sample (analyzed immediately after essential oil collection), the amount of linalool and camphor increased in all samples stored in all conditions of temperature and time, with the exception of the samples stored for nine months at room temperature. On the other hand, limonene and camphene contents decreased during the storage treatments, showing that the highest content of these compounds occurred in the non-stored treatment. Essential oil storage at the freezer temperature and for three months storage time resulted in the highest average value of the major constituents, highlighting these as the best conditions for obtaining the highest content of the major compounds.