Optimization of Callus and Cell Suspension Cultures of Lycium schweinfurthii for Improved Production of Phenolics, Flavonoids, and Antioxidant Activity

The effect of plant growth regulators, FeO3-CTs nanoparticles and LEDs light on the growth and biochemical compounds of black seed (Nigella sativa L.) callus in vitro

BACKGROUND

black seed (Nigella sativa L.) has long been utilized in traditional medicine and as a food ingredient due to its potential therapeutic properties including its effectiveness against cancer, coronaviruses, and bacterial infections. Recently, it has garnered significant attention for its rich reservoir of beneficial secondary metabolites. In vitro culture of black seeds presents an efficient and modern approach for the large-scale production of these valuable compounds, offering advantages such as space efficiency, reduced time, and lower costs. This study aimed to develop and optimize a protocol for callus induction and the identification of key secondary metabolites, including thymoquinone (TQ), phenolic compounds, and flavonoids. To induce callus formation in seed explants, two plant growth regulators (PGRs) were applied individually or in combination and incorporated into Murashige and Skoog (MS) culture medium.

RESULTS

The combination of Auxin, 2,4-dichlorophenoxyacetic acid (2,4-D) and cytokinin, 6-benzylaminopurine (BAP), effectively induced callus formation in most explants, with the response varying based on concentration. The highest callus fresh weight (7.02 g) was obtained on Red(R) LED lighting with FeO3-CTs nanoparticles (100 mg/L- 1), which also resulted in the highest dry weight (1.307 g) after 40 days of cultivation. Similarly, the highest levels of phenols, flavonoids and amino acids were observed under R LED with FeO3-CTs nanoparticles (100 mg L- 1), while FeO3-CTs nanoparticles at 100 and 200 mg/L- 1) exhibited significant effects on metabolite production. In contrast, the antioxidant activity against DPPH free radicals and total carbohydrate accumulation were enhanced in callus cultures treated with FeO3-CTs nanoparticles (200 mg/L- 1) under dark conditions. Additionally, GC-MS analysis revealed that FeO3-CTs nanoparticles (100 mg/L- 1) yielded the most effective enhancement of secondary metabolites under blue (B) LED light at a concentration of 295 mg/L- 1.

CONCLUSION

The finding of this study highlights the potential of the proposed method for the large-scale production of secondary metabolites, total carbohydrates, amino acids, phenolic compounds, and flavonoids from black seed callus cultures in a controlled environment. This optimized approach offers a cost-effective and space-efficient strategy for enhancing bioactive compound synthesis, with potential applications in pharmaceutical and nutraceutical industries.

Characteristics of Callus and Cell Suspension Cultures of Highbush Blueberry (Vaccinium corymbosum L.) Cultivated in the Presence of Different Concentrations of 2,4-D and BAP in a Nutrient Medium

In this work, cultures of callus and suspension cells originating from leaves of sterile highbush blueberry (Vaccinium corymbosum L.) plants were obtained and characterized. For their active growth and production of phenolic compounds, a combination of 2,4-D at a concentration of 0.34-2.25 µM and BAP at a concentration of 0.45-2.25 µM is effective. An increase in the phytohormone concentration leads to a slowdown in culture formation and reduces their ability to synthesize phenolic compounds. When cultivating V. corymbosum suspension cells over a year (12 passages), they not only retain the ability to synthesize phenolic compounds but also enhance it. By the 12th passage, the content of TSPC in suspension cells reaches 150 mg/g DW, the content of flavonoids reaches 100 mg/g DW, the content of flavans reaches 40 mg/g DW, and the content of proanthocyanidins reaches 30 mg/g DW. The high content of phenolic compounds may be due to the high expression of genes in flavonoid biosynthesis enzymes. V. corymbosum suspension cells accumulate a high level of phenolic compounds during a passage. The ability of V. corymbosum callus and cell suspension cultures in the presence of low concentrations of phytohormones to grow and accumulate biologically active phenolic compounds determines their high economic significance and prospects for organizing a biotechnological method for obtaining phenolic compounds.

Elucidating the efficacy of functionalized multi-walled carbon nanotube in the biogenesis of L-Dopa and antioxidant metabolites in cell cultures of Hybanthus enneaspermus

Hybanthus enneaspermus (L.)F.Muell. is a highly indispensable medicinal herb yielding L-Dopa, deemed the gold standard drug among the therapeutic options for Parkinson's disease. This investigation is the first attempt to evaluate the eliciting influence of carboxylic acid functionalized multi-walled carbon nanotube (MWCNT-COOH) on the biosynthesis of L-Dopa and on biomass aggregation and antioxidant metabolites in H. enneaspermus cell suspension cultures. Suspension cells were accomplished from friable calli generated from the nodal segments of H. enneaspermus in Murashige and Skoog (MS) liquid medium infused with 2 mg L-1 2, 4-Dichlorophenoxyacetic acid (2, 4-D), and 0.3 mg L-1meta-Topolin (mT). The influence of MWCNTs on L-Dopa synthesis, biomass accumulation, and biochemical parameters was examined on the basis of the exposure time and in a concentration-dependent manner of MWCNTs. The inclusion of 30 mg L-1 MWCNTs increased the biomass and the L-Dopa level by 2.00 and 16.37-folds, respectively, compared with that of the control. Furthermore, the effect of MWCNTs on physiological parameters such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), ascorbate peroxidase (APX), hydrogen peroxide (H2O2), malondialdehyde (MDA) content, 2-diphenylpicrylhydrazyl (DPPH), and ferric-reducing ability of plasma (FRAP) was examined over the elicited cells. Among the antioxidant enzymatic activities, CAT enhanced 8.0 fold compared with that of the control. MDA and DPPH content enhanced 2.60 and 1.12 folds, respectively, compared with that of the control. The current study showed that MWCNTs offer new possibilities for their usage over in vitro by acting as potential innovative plant metabolite elicitors and stress-protecting entities.

Performance of Malaysian kenaf Hibiscus cannabinus callus biomass and exopolysaccharide production in a novel liquid culture

The versatility of a well-known fibrous crop, Hibiscus cannabinus (kenaf) is still relatively new to many. Kenaf's potential applications, which can be extended even into critical industries such as pharmaceutical and food industries, have always been overshadowed by its traditionally grown fiber. Therefore, this study aimed to venture into the biotechnological approach in reaping the benefits of kenaf through plant cell suspension culture to maximize the production of kenaf callus biomass (KCB) and exopolysaccharide (EPS), which is deemed to be more sustainable. A growth curve was established which indicates that cultivating kenaf callus in suspension culture for 22 days gives the highest KCB (9.09 ± 1.2 g/L) and EPS (1.1 ± 0.02 g/L). Using response surface methodology (RSM), it was found that sucrose concentration, agitation speed, and naphthalene acetic acid (NAA) concentration can affect the production of KCB and EPS significantly (p < 0.05) while 2,4-dichlorophenoxy acetic acid (2,4-D) was deemed insignificant. To maximize the final yield of KCB and EPS, the final optimized variables are 50 g/L sucrose, 147.02 rpm, and 2 mg/L of NAA. To conclude, the optimized parameters for the cell suspension culture of kenaf callus serve as the blueprint for any sustainable large-scale production in the future and provide an alternative cultivating method to kenaf traditional farming.

Biochemical changes and enhanced accumulation of phenolic compounds in cell culture of Perilla frutescens (L.) by nano-chemical elicitation

Perilla frutescens (L.) Britt is a renowned medicinal plant with pharmaceutically valuable phenolic acids and flavonoids. The present study was aimed to study the eliciting effect of silver and copper nanoparticles (AgNPs and CuNPs, 50 and 100 mg/L), and methyl jasmonate (MeJa, 50 and 100 μM) on the biochemical traits, the accumulation of phenolic compounds and antioxidative capacity of P. frutescens cell suspension culture. Suspension cells were obtained from friable calli derived from nodal explants in Murashige and Skoog (MS) liquid medium containing 1 mg/L 2,4-D and 1 mg/L BAP. The 21 days old cell suspension culture established from nodal explant derived callus supplemented with 100 mg/L MeJa resulted in the highest activity of catalase and guaiacol peroxidase enzymes, and CuNPs 100 mg/L treated cells indicated the maximum content of total phenol, total anthocyanin, superoxide dismutase, malondialdehyde, and H2O2. Also, the highest content of ferulic acid (1.41 ± 0.03, mg/g DW), rosmarinic acid (19.29 ± 0.12, mg/g DW), and phenylalanine ammonia-lyase (16.81 ± 0.18, U/mg protein) were observed with 100 mg/L CuNPs, exhibiting a total increase of 1.58-fold, 2.12-fold, and 1.51-fold, respectively, higher than untreated cells. On the other hand, AgNPs 100 mg/L treated cells indicated the most amounts of caffeic acid (0.57 ± 0.03, mg/g DW) and rutin (1.13 ± 0.07, mg/g DW), as well as the highest scavenging potential of free radicals. Overall, the results of the present study can be applied for the large-scale production of valuable phenolic acids and flavonoids from P. frutescens through CuNPs and AgNPs 100 mg/L elicited cell suspension cultures.

Wood anatomy and dendrochronological potentiality of some woody shrubs from the southern Mediterranean coast in Egypt

In tropical and subtropical regions, much research is still required to explore the dendrochronological potential of their trees. This study aims to evaluate the anatomical structure and dendrochronological potential of three Mediterranean desert shrubs in Egypt (Lycium schweinfurthii var. schweinfurthii, L. europaeum, and Calligonum polygonoides subsp. comosum) supported by X-ray density. The results showed that the target species had distinct growth rings at macroscopic and microscopic levels. The vessel traits reflected the adaptability of each species with the prevailing arid climate conditions. After the exclusion of the non-correlated series, we obtained three site chronologies that cover the years 2013-2022 for L. schweinfurthii, 2012-2022 for L. europaeum, and 2011-2022 for C. comosum. The mean series intercorrelation was 0.746, 0.564, and 0.683 for L. schweinfurthii, L. europaeum, and C. comosum, respectively. The EPS (expressed population signal) values ranged from 0.72 to 0.80, while the SNR (species-to-noise ratio) ranged from 9.1 to 21.5. Compiling all series of L. schweinfurthii raised the EPS value to 0.86. The chronologies developed for the studied species were relatively short since we dealt with multi-stemmed shrubs. The average percentage difference between latewood density (LWD) and earlywood density (EWD) in C. comosum, L. europaeum, and L. schweinfurthii were 11.8% ± 5.5, 5.2%± 1.87, and 3.6% ± 1.86, respectively. X-ray densitometry helped in the precise determination of the ring borders of the studied species. The relationships between the radial growth of the studied species and the climate variables were weak to moderate but mostly not significant (i.e., r < 0.7). Generally, the radial growth of the target species had a weak to moderate positive correlation with temperature and precipitation during the wet season (winter), while negatively correlated with temperature for the rest of the year, particularly in summer. Our data agrees with earlier findings that ring formation starts at the beginning of the long vegetative stage, then the rest of the assimilated carbohydrates are directed to the flowering and fruiting at the end of the vegetative stages. For more efficient dendrochronological studies on subtropical and Mediterranean trees, we recommend carrying out xylogenesis studies, collection of phenological data, sampling 45-80 trees per species, using new techniques, and choosing homogeneous and close sites for wood sampling.

Chemical and Biological Properties of Three Poorly Studied Species of Lycium Genus-Short Review

The genus Lycium belongs to the Solanaceae family and comprises more than 90 species distributed by diverse continents. Lycium barbarum is by far the most studied and has been advertised as a “superfood” with healthy properties. In contrast, there are some Lycium species which have been poorly studied, although used by native populations. L. europaeum, L. intricatum and L. schweinfurthii, found particularly in the Mediterranean region, are examples of scarcely investigated species. The chemical composition and the biological properties of these species were reviewed. The biological properties of L. barbarum fruits are mainly attributed to polysaccharides, particularly complex glycoproteins with different compositions. Studies regarding these metabolites are practically absent in L. europaeum, L. intricatum and L. schweinfurthii. The metabolites isolated and identified belong mainly to polyphenols, fatty acids, polysaccharides, carotenoids, sterols, terpenoids, tocopherols, and alkaloids (L. europaeum); phenolic acids, lignans, flavonoids, polyketides, glycosides, terpenoids, tyramine derivatives among other few compounds (L. schweinfurthii), and esters of phenolic acids, glycosides, fatty acids, terpenoids/phytosterols, among other few compounds (L. intricatum). The biological properties (antioxidant, anti-inflammatory and cytotoxic against some cancer cell lines) found for these species were attributed to some metabolites belonging to those compound groups. Results of the study concluded that investigations concerning L. europaeum, L. intricatum and L. schweinfurthii are scarce, in contrast to L. barbarum.