Phenotypic Variations and Bioactive Constituents among Selected Ocimum Species

Basil (Ocimum species) represents an extraordinary group of aromatic plants that have gained considerable economic importance, primarily due to their essential oils, which have applications in medicine, culinary, and perfumery. The Ocimum genus encompasses more than 60 species of herbs and shrubs originally native to tropical regions. This genus stands out for its remarkable diversity, displaying a wide spectrum of variations in phenotype, chemical composition, and genetic makeup. In addition to genetic factors, the growth, development, and essential oil production of basil are also influenced by environmental conditions, ontogeny, and various other factors. Consequently, the primary objective of this study was to explore the diversity in both the morphological characteristics and essential oil composition among basil genotypes preserved within the gene bank of the Hungarian University of Agriculture and Life Sciences' Department of Medicinal and Aromatic Plants. The investigation involved the assessment of fifteen basil genotypes, representing four distinct species: Ocimum basilicum (including 'Anise', 'Clove', 'Fino Verde', 'Licorice', 'Mammoth', 'Mrs. Burns', 'Thai tömzsi', 'Thai hosszú', and 'Vietnamese basil'), Ocimum sanctum (green holy basils), Ocimum citrodora (Lemon basil), and Ocimum gratissimum (African and Vana holy basil). The genotypes exhibited significant variations in their morphological growth, essential oil content (EOC), and composition. African basil produced more biomass (408.3 g/plant) and showed robust growth. The sweet basil cultivars clove, licorice, Thai tömzsi, and Thai hosszú also exhibited similar robust growth trends. Vietnamese basil, on the other hand, displayed the lowest fresh biomass of 82.0 g per plant. Both holy basils showed EOC levels below 0.5%, while Mrihani basil stood out with the highest EOC of 1.7%. The predominant constituents of the essential oil among these genotypes comprised estragole, thymol, methyl cinnamate, linalool, and eugenol. In conclusion, this study showed that the genotypes of basil stored in the department's gene bank exhibit a wide range of variability, both within and between species.

Basil (Ocimum basilicum) Landraces Can Be Used in a Water-Limited Environment

Basil (Ocimum basilicum L.) is a member of the Labiatae family and is one of the most widely consumed aromatic and medicinal plants in many countries due to its numerous properties and uses. The objective of the study was to determine whether landraces are better adapted to water-limited environments compared to commercial cultivars. Irrigation levels and genotypes affected plant height and leaf area index, with 25% and 33% higher values observed under complete irrigation, respectively. Additionally, limited water availability resulted in a 20% reduction in dry matter yield and a 21% reduction in essential oil yield over the three years in all of the genotypes tested, specifically in the lower irrigation treatment (d₄₀), compared to the control treatment (d₁₀₀). The landraces that performed the best under limited water supply were Athos white spike (AWS) and Gigas white spike (GWS), indicating their suitability for environments with limited water resources. The results demonstrate that there are landraces that can be utilized in dryland climates with appropriate water management, enabling water conservation and utilization of fields in water-scarce areas for irrigation purposes.

The effect of harvest time on the natural product of Rosmarinus officinalis L. from South Iran (Fars province)

The medicinal composition of rosemary essential oil has led to its widespread use in the food, cosmetic, health and herbal industries. In the present work, seasonal variations of essential constituents of essential oil, essential oil yield were evaluated. The predominant components of rosemary were: camphene, limonene, α-pinene, camphor, borneol, linalool, 1,8-cineole, (E)- caryophyllene and bornyl acetate. The highest rate of linalool was seen in summer, while camphor, limonene and borneol showed the highest percentage in cold season. Some of the compounds such as α-pinene, camphene, bornyl acetate and (E)- caryophyllene in the spring with the activation of some important plant enzymes such as peroxidase showed the highest amount. It is hoped that this research will provide very useful information about the best time to harvest the valuable rosemary plant and can be useful for the health, food and herbal industries that use this plant.

Application of Super Absorbent Polymer and Plant Mucilage Improved Essential Oil Quantity and Quality of Ocimum basilicum var. Keshkeni Luvelou

One of the major factors limiting the production of medicinal plants in arid and semi-arid areas is water deficit or drought stress. One-third of the land in the world is arid and semi-arid and is inhabited by nearly 4 × 10⁸ people. Ocimum basilicum (sweet basil) is a valuable medicinal plant that is sensitive to water deficit, and water shortage negatively affects sweet basil yield and quality. Water availability in the root zone of basil could ameliorate the negative effects of water shortage. To the best of our knowledge, although the effects of hydrophilic polymers (HPs) have been studied in different agricultural crops, the effects of HP application in medicinal plants have not been previously investigated. This investigation was conducted to explore the effects on water use efficiency when using Stockosorb^® (STS) and psyllium seed mucilage (PSM) as hydrophilic polymers (HPs) and the effects of these HPs on essential oil quality, quantity, and yield. The research was set up in a factorial experiment on the basis of completely randomized block design with three replications. We used two HPs, STS (industrial) and PSM (herbal), with two methods of application (mixed with soil, mixed with soil + root) at four concentrations (0%, 0.1%, 0.2%, and 0.3% (w/w)). Results showed that the STS and PSM significantly increased the dry herb yield (both shoot and root) in comparison to the control, and the improving effect was higher when these HPs were mixed with soil + root. The highest dry herb yield (6.74 and 3.68 g/plant for shoot and root, respectively) was detected in the PSM at 0.1% mixed with soil + root. There was not any significant difference in dry herb yield among PSM (0.1%), PSM (0.2%), and STS (0.2%) when mixed with soil + root. Soil application of PSM and soil + root application of STS at a concentration of 0.3% increased the Essential Oil (EO) content almost three-fold in comparison to the control (0.5% and 0.52% to 0.18% v/w, respectively). The maximum essential oil yield was recorded in plants treated with STS (0.2% in) or PSM (0.1%) by soil + root application (0.21 and 0.19 mL/plant, respectively). PSM at concentrations of 0.1% and 0.2% (mixed with soil + root) showed the highest water use efficiency (1.91 and 1.82 g dry weight (DW)/L H₂O, respectively). STS mixed with soil also significantly improved water use efficiency (WUE) in comparison to the control. The application of these HPs improved the quality of sweet basil essential oil by increasing the linalool and decreasing the eugenol, epi-α-cadinol, and trans-α-bergamotene content.