An update on biotechnological intervention mediated by plant tissue culture to boost secondary metabolite production in medicinal and aromatic plants

Since prehistoric times, medicinal and aromatic plants (MAPs) have been employed for various therapeutic purposes due to their varied array of pharmaceutically relevant bioactive compounds, i.e. secondary metabolites. However, when secondary metabolites are isolated directly from MAPs, there is occasionally very poor yield and limited synthesis of secondary metabolites from particular tissues and certain developmental stages. Moreover, many MAPs species are in danger of extinction, especially those used in pharmaceuticals, as their natural populations are under pressure from overharvesting due to the excess demand for plant-based herbal remedies. The extensive use of these metabolites in a number of industrial and pharmaceutical industries has prompted a call for more research into increasing the output via optimization of large-scale production using plant tissue culture techniques. The potential of plant cells as sources of secondary metabolites can be exploited through a combination of product recovery technology research, targeted metabolite production, and in vitro culture establishment. The plant tissue culture approach provides low-cost, sustainable, continuous, and viable secondary metabolite production that is not affected by geographic or climatic factors. This study covers recent advancements in the induction of medicinally relevant metabolites, as well as the conservation and propagation of plants by advanced tissue culture technologies.

Advances in efficient extraction of essential oils from spices and its application in food industry: A critical review

With the increase of people's awareness of food safety, it is crucial to find natural and green antimicrobial agents to replace traditional antimicrobial agents. Essential oils of spices (SEOs) are low toxicity or nontoxic, which exhibited antioxidants and antimicrobial activity according to many in vitro and in situ experiments. Spices are widely available and low cost as a plant raw material for the extraction of SEOs. This review summarized highly efficient extraction techniques for SEOs, such as physical field assisted extraction technology, supercritical fluid extraction, and biological-based techniques. Furthermore, purification of SEOs and components were also recapitulated. Purification techniques of SEOs improve their utilization value due to the increased content of bioactive components. Finally, the review concentrated on the applications of SEOs in food industry, including food preservation, food active packaging by means of films or coatings, antioxidant properties. In addition, addressing the problem of unstability of SEOs and its role to inhibit the pathogenic bacteria, the encapsulation of SEOs for use in the food industrial sectors reduces the safety risk to human health.

Seasonal Variation in Chemical Compositions of Essential Oils Extracted from Lavandin Flowers in the Yun-Gui Plateau of China

Lavandin, as an important cash crop, is cultivated in Kunming, Yun-Gui Plateau of China. For the special growing environment, Lavandin was grown here and used to investigate the changes in the yield and chemical compositions of essential oils extracted from the flowers in different seasons. The essential oils were extracted by hydro-distillation and analysis by gas chromatography-mass spectrometry (GC-MS). Results indicated great changes in chemical composition depending on the season of harvesting. The yields of essential oils ranged from 2.0% to 3.8% among the seasons, and the highest yield was in the summer. Chemical composition data showed that the extracted oils were rich in oxygenated monoterpenes (55.4-81.4%), eucalyptol (38.7-49.8%), camphor (8.41-14.26%), α-bisabolol (6.6-25.5%), and linalool (4.6-12.5%). The contents of eucalyptol and α-bisabolol changed in a contrary trend with seasonal variations. The results provided new insight for Chinese Lavandin germplasm to be used in application and development, and reference to the researcher, the farmer, and investor for sustainable industrialization of the plant grown in the Yun-Gui Plateau of China, but also the similar plateau area of the sustainable developments.

Effect of AuNPs and AgNPs on the Antioxidant System and Antioxidant Activity of Lavender (Lavandula angustifolia Mill.) from In Vitro Cultures

The aim of this study was to determine the effect of gold and silver nanoparticles on the activity of antioxidant enzymes (ascorbate peroxidase (APX), superoxide dismutase (SOD), guaiacol peroxidase (POX), and catalase (CAT)), the free radical scavenging capacity, and the total polyphenol capacity of lavender (Lavandula angustifolia Mill.) cultivar “Munstead” propagated in vitro. In the experiment, fragments of lavender plants were cultivated in vitro on medium with the addition of 1, 2, 5, 10, 20, and 50 mg∙dm⁻³ of AgNPs or AuNPs (particle sizes 24.2 ± 2.4 and 27.5 ± 4.8 nm, respectively). It was found that the nanoparticles increase the activity of the antioxidant enzymes APX and SOD; however, the reaction depends on the NP concentration. The highest APX activity is found in plants propagated on media with 2 and 5 mg∙dm⁻³ of AgNPs. AuNPs significantly increase the APX activity when added to media with a concentration of 10 mg∙dm⁻³. The highest SOD activity is recorded at 2 and 5 mg∙dm⁻³ AgNP and AuNP concentrations. The addition of higher concentrations of nanoparticles to culture media results in a decrease in the APX and SOD activity. The addition of AuNPs to culture media at concentrations from 2 to 50 mg∙dm⁻³ increases the POX activity in comparison to its activity when AgNPs are added to the culture media. No significant influence of NPs on the increase in CAT activity was demonstrated. AgNPs and AuNPs increased the free radical scavenging capacity (ABTS^•+). The addition of NPs at concentrations of 2 and 5 mg∙dm⁻³ increased the production of polyphenols; however, in lower concentrations it decreased their content in lavender tissues.

Effect of Jasmonic Acid and Salicylic Acid on Growth and Biochemical Composition of In-Vitro-Propagated Lavandula angustifolia Mill

This study assessed the effect of jasmonic acid (JA) and salicylic acid (SA) on the in vitro development and production of Lavandula angustifolia Mill. plant material, and the accumulation of polyphenols, chlorophylls, and carotenoids in explants. Results were compared with explants grown in control media and with in-vivo-grown mature and young L. angustifolia plants. After 21 days of incubation, all explants propagated on low-SA-concentration or elicitor-free media produced a greater number of shoots than explants cultivated on media with higher elicitor concentrations. Shoots grew taller when activated charcoal (AC) was added to the elicitor-supplemented media, while AC negatively affected or had no effect on the phytochemical composition of plants. Explants grown in the presence of elicitors had higher polyphenolic and chlorophyll content than the controls, demonstrating the beneficial impact of elicitors on the secretion of secondary metabolites. Lutein and β-carotene were the dominating carotenoids in all samples. Culture media supplemented with 0.5 mg/L JA and 1.5 mg/L SA + AC proved the most suitable to produce plant material with high polyphenol and carotenoid content, comparable with in-vivo-grown plants.

Gas Chromatography-Mass Spectrometry (GC-MS) Analysis of Essential Oils from AgNPs and AuNPs Elicited Lavandula angustifolia in vitro Cultures

The aim of this study was to determine how the addition of gold and silver nanoparticles to culture media affects the composition of essential oils extracted from Lavandula angustifolia propagated on MS media with the addition of 10 and 50 mg·dm⁻³ of gold (24.2 ± 2.4 nm) and silver (27.5 ± 4.8 nm) nanocolloids. The oil extracted from the lavender tissues propagated on the medium with 10 mg·dm⁻³ AgNPs (silver nanoparticles) differed the most with respect to the control; oil-10 compounds were not found at all, and 13 others were detected which were not present in the control oil. The addition of AuNPs (gold nanoparticles) and AgNPs to the media resulted in a decrease of lower molecular weight compounds (e.g., α- and β-pinene, camphene, δ-3-carene, p-cymene, 1,8-cineole, trans-pinocarveol, camphoriborneol), which were replaced by those of a higher molecular weight (τ- and α-cadinol 9-cedranone, cadalene, α-bisabolol, cis-14-nor-muurol-5-en-4-one, (E,E)-farnesol).

Essential oil obtained from micropropagated lavender, its effect on HSF cells and application in cosmetic emulsion as a natural protective substance

The aim of the study was to determine the influence of the essential oils isolated from the field - grown and micropropagated in vitro narrow - leaved lavender of the 'Munstead' cultivar, on human skin cells, and their capability to synthesise procollagen. The amount of procollagen type I produced by fibroblast cells was determined using ELISA kit. Essential oil isolated from micropropagated lavender was further used as a protective ingredient against the development of microorganisms in O/W cosmetic emulsion. The presented results demonstrate that the use of 0.01, 0.001 and 0.0001% essential oils isolated from in vitro plants stimulate HSF cells to the production of procollagen. It was further performed that the tested essential oil used in the concentration of 0.1% in a cosmetic emulsion is characterised by preservative effect for cosmetic preparations for the period of 3 months.