Amounts Of Secondary Metabolites Research Articles

Phytochemical Screening and Antioxidant Activity of <i>Annona Senegalensis</i> Extracts (Leaves and Stem Bark) Collected from Three Regions of Senegal

The main objective of the present study is to focus on evaluation of the secondary metabolites composition and antioxidant activity of hydro – ethanolic extracts of <i>Annona senegalensis</i> leaves and stem bark which used in traditional medicine against several kind of diseases. The yields of hydro-ethanolic extracts of organs (leaves and Stem bark) were determined, followed by phytochemical screening and amount of secondary metabolites, by using conventional analytical methods. Anti-radical activity was carried out by DPPH (2, 2-diphenyl-l-picrylhydrazyl) reduction tests. The best extraction rates, whatever the plant organ or origin, were obtained with leaves (15.5% on average). Phytochemical screening revealed the presence of polyphenols, flavonoids and tannins. The highest levels of total polyphenols were obtained with leaves extracts [83.931 ± 0.018 g EGA/100 g Dry Matter (DM)] compared with stem bark (77.886 ± 1.001 g EGA/100 g DM). The highest tannin and flavonoid contents are 1.093 ± 0.006 g EC/100 g DM and 0.195 ± 0.004 g EC/100 g DM, respectively. Moreover, the extracts have a high antioxidant capacity with high inhibition percentages of 95.06 ± 0.10% for the leaves and 92.87 ± 0.10% for the bark. These results highlight the presence of bioactive compounds and potential antioxidant activity that have been shown to be efficient in the treatment of certain diseases, in accordance with ethno - botanical survey.

In Vitro Synthetic Polyploidization in Medicinal and Aromatic Plants for Enhanced Phytochemical Efficacy—A Mini-Review

Medicinal and aromatic plants (MAPs) are well known for their valuable secondary metabolites and diverse phytochemicals responsible for a plethora of medicinal properties such as antimicrobial, antioxidant, anti-inflammatory, anticancerous, and analgesic activities, making them essential for various industries. Therefore, this significant market demand has led to the need to improve the quality and quantity of secondary metabolites and thus develop high-quality commercial products. In this context, polyploidization is considered a sound contemporary approach that produces new genotypes, leading to the overexpression of genes involved in biosynthesizing crucial metabolites. Enhanced natural metabolite production increases the biological activities of plant extracts along with enhanced tolerance against abiotic and biotic stresses to achieve homogeneity. This improvisation in the quality and quantity of plant secondary metabolites can maximize the medicinal value of the plants. Therefore, this mini-review aims to explore the importance of enhancing biological activity in medicinal plants, summarize the progress of synthetic polyploidization as a breeding tool in MAP species, and elucidate how this technique plays an important role in improving medicinal values. This breeding strategy could significantly advance future research and industrial applications by inducing superior genotypes with enhanced genomic complexity and improving traits like increased biomass, stress tolerance, and novel biochemical pathways. So, it can be concluded that in vitro synthetic polyploidization can be an effective tool for promoting the production of more distinctive genotypes with immense medicinal properties for a variety of commercial and pharmaceutical purposes.

The repertoire and levels of secondary metabolites in microbial cocultures depend on the inoculation ratio: a case study involving Aspergillus terreus and Streptomyces rimosus

ObjectiveThe aim of this study was to determine the influence of the inoculation volume ratio on the production of secondary metabolites in submerged cocultures of Aspergillus terreus and Streptomyces rimosus.ResultsThe shake flask cocultures were initiated by using 23 inoculum variants that included different volumes of A. terreus and S. rimosus precultures. In addition, the axenic controls were propagated in parallel with the cocultures. UPLC‒MS analysis revealed the presence of 15 secondary metabolites, 12 of which were found both in the “A. terreus vs. S. rimosus” cocultures and axenic cultures of either A. terreus or S. rimosus. The production of the remaining 3 molecules was recorded solely in the cocultures. The repertoire and quantity of secondary metabolites were evidently dependent on the inoculation ratio. It was also noted that detecting filamentous structures resembling typical morphological forms of a given species was insufficient to predict the presence of a given metabolite.ConclusionsThe modification of the inoculation ratio is an effective strategy for awakening and enhancing the production of secondary metabolites that are not biosynthesized under axenic conditions.

Antioxidant and phytochemical analysis of different date palm (Phoenix dactylifera l.) Seed varieties: An in vitro assessment

The date palm (Phoenix dactylifera L.) fruit contains variety of bioactive constituents including phenolic compounds. This research aimed to analyze the phenolic constituents and antioxidant potential of crude methanol extract samples from seeds of different date varieties, Aseel (As), Ambar (Am), Ajwa Saudi (AJS), Ajwa Khairpur (AJK), Khipro (KP) and Karblyan (KB). Date seeds are regarded as waste product. However, it contains secondary chemicals of biomedical significance. Colorimetric methods were used for the evaluation of phytochemical and antioxidant capacity. The Folin-Ciocalteu method was used for the assessment of phenolic content. The antioxidant potential was evaluated through phosphomolybdenum test, potassium ferricyanide test, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate scavenging test methods. All samples differ significantly in terms of antioxidant activities and quantity of secondary metabolites (phenolic and flavonoid contents). When all samples were compared, As was shown to have the highest amount of phenolic and flavonoids, while AJ(S) had the lowest content. The KP sample had the highest overall antioxidant and reducing potential, while the AJ(K) and Am samples showed the lowest, respectively. Significant DPPH scavenging capacity has been demonstrated in all samples. In order to extend the shelf life of food products, date seeds may consequently provide ideal material for the bio-functional food industry.

Synthetic polyploidization induces enhanced phytochemical profile and biological activities in Thymus vulgaris L. essential oil

Essential oil from Thymus vulgaris L. has valuable therapeutic potential that is highly desired in pharmaceutical, food, and cosmetic industries. Considering these advantages and the rising market demand, induced polyploids were obtained using oryzalin to enhance essential oil yield. However, their therapeutic values were unexplored. So, this study aims to assess the phytochemical content, and antimicrobial, antioxidant, and anti-inflammatory activities of tetraploid and diploid thyme essential oils. Induced tetraploids had 41.11% higher essential oil yield with enhanced thymol and γ-terpinene content than diploid. Tetraploids exhibited higher antibacterial activity against all tested microorganisms. Similarly, in DPPH radical scavenging assay tetraploid essential oil was more potent with half-maximal inhibitory doses (IC50) of 180.03 µg/mL (40.05 µg TE/mg) than diploid with IC50 > 512 µg/mL (12.68 µg TE/mg). Tetraploids exhibited more effective inhibition of in vitro catalytic activity of pro-inflammatory enzyme cyclooxygenase-2 (COX-2) than diploids at 50 µg/mL concentration. Furthermore, molecular docking revealed higher binding affinity of thymol and γ-terpinene towards tested protein receptors, which explained enhanced bioactivity of tetraploid essential oil. In conclusion, these results suggest that synthetic polyploidization using oryzalin could effectively enhance the quality and quantity of secondary metabolites and can develop more efficient essential oil-based commercial products using this induced genotype.

The impact of nitrogen fertilization on the alkaloid content and growth traits of Datura (Datura stramonium L.)

D. stramonium is a wild plant species belonging to the nightshade family Solanaceae and grows on the edges of cotton fields, empty lands and roadsides. The plant is one of the most important economic weed plants that contain both toxic and medicinal properties. Studies have shown that the plant contains toxic tropane alkaloids such as atropine, hyoscyamine, and scopolamine. It is known that cultivation techniques have a great influence on the quality and quantity of secondary metabolites. For this reason, it is important to determine the optimal values of the agronomic factors that influence plant growth and production. This study was conducted in the experimental area of the Agricultural Faculty of Dicle University in the 2010 and 2011 growing seasons so as to evaluate the impact of nitrogen fertilizer rates (0, 50, 100 and 200 kg ha-1) on some agronomical characteristics such as fresh and dry herb yield and total alkaloid content of Datura (Datura stramonium L.). The results revealed that significant (P?0.05) differences were observed between nitrogen doses in the 2010 and 2011 growing seasons in terms of seed yield, fresh and dry herb yield and total alkaloid yield of seeds. However, seed yield changed between 545 kg ha-1 and 625 kg ha-1, fresh herb yield between 8000 and 24483 kg ha-1, dry herb yield between 2190 kg ha-1 and 5083 kg ha-1 and alkaloid content between 0.259% and 0.366%, respectively. The results showed that fresh and dry herb yields increased with increasing nitrogen doses.

Phytochemical Screening of Secondary Metabolites, Antioxidant and Antibacterial Activities of Kalangkala Plant (Litsea Angulata): A Review Article

Litsea angulata, more commonly known as Kalangkala, is a type of plant that belongs to the Lauraceae family. Empirically, the plant has been used traditionally by local people for the treatment of boils, diarrhea, stomachache, dyspepsia, gastroenteritis, diabetes, insect bites, and anti-irritation. This review article aims to find out the results of phytochemical screening of metabolites from parts of Kalangkala plant with various solvents as well as the results of the tests of antioxidant and antibacterial activities that several researchers have carried out. The method used was a literature search on Google Scholar and Pubmed with the keywords kalangkala, Litsea angulata, phytochemical screening, antioxidant, and antibacterial. The results of this review showed that various solvents, such as water, ethanol, methanol, N-hexane, and ethyl acetate in seed, fruit flesh, bark, stem, and leave parts of Kalangakala plant produces different amounts of secondary metabolites. Secondary metabolites such as alkaloids, flavonoids, saponins, and tannins extracted well using etanol as a solvent due to their polarity. The results of the antioxidant activity showed that the part of kalangakala plant such as the bark of the tree, has a very good antioxidant activity of 2.41 ppm when tested using ethyl acetate solvent. Furthermore, the results of the antibacterial activity test show an inhibition of 50 mm on S. mutans bacteria when tested using ethanol solvent. In conclusion, kalangkala plant has secondary metabolites which act as antioxidants and antimicrobials that also potential to developed as traditional medicine.

Exposure to single-walled carbon nanotubes differentially affect in vitro germination, biochemical and antioxidant properties of Thymus daenensis celak. seedlings

Carbon nanomaterials such as single-walled carbon nanotubes (SWCNTs) offer a new possibility for phyto-nanotechnology and biotechnology to improve the quality and quantity of secondary metabolites in vitro. The current study aimed to determine the SWCNTs effects on Thyme (Thymus daenensis celak.) seed germination. The seedlings were further assessed in terms of morphological and phytochemical properties. Sterile seeds were cultured in vitro and treated with various concentrations of SWCNTs. Biochemical analyses were designed on seedling sample extracts for measuring antioxidant activities (AA), total flavonoids (TFC) and phenolic contents, and the main enzymes involved in oxidative reactions under experimental treatments. The results indicated that an increase in SWCNTs concentration can enhance the total percentage of seed germination. The improvement was observed in samples that received SWCNTs levels of up to 125 µg ml−1, even though seedling height and biomass accumulation decreased. Seedling growth parameters in the control samples were higher than those of grown in SWCNT-fortified media. This may have happened because of more oxidative damage as well as a rise in POD and PPO activities in tissues. Additionally, secondary metabolites and relevant enzyme activities showed that maximum amounts of TPC, TFC, AA and the highest PAL enzyme activity were detected in samples exposed to 62.5 µg ml−1 SWCNTs. Our findings reveal that SWCNTs in a concentration-dependent manner has different effects on T. daenensis morphological and phytochemical properties. Microscopic images analysis revealed that SWCNTs pierce cell walls, enter the plant cells and agglomerate in the cellular cytoplasm and cell walls. The findings provide insights into the regulatory mechanisms of SWCNTs on T. daenensis growth, germination and secondary metabolites production.

Ultraviolet-B and Heavy Metal-Induced Regulation of Secondary Metabolites in Medicinal Plants: A Review.

Despite a rich history and economic importance, the potential of medicinal plants has not been fully explored under different abiotic stress conditions. Penetration of UV-B radiation and contamination of heavy metals are two important environmental stress for plants with remarkable influence on the defense-related and pharmaceutically important secondary metabolites of medicinal plants. UV-B and heavy metal contamination may become a critical issue that either positively or negatively affects the quality and quantity of secondary metabolites. Such effects may result from changes in the expression level of genes that encode the corresponding enzymes or the inactivation and/or stimulation of specific enzymes involved in the different biosynthetic pathways of the secondary metabolites. Therefore, a comprehensive study of the impact of UV-B and heavy metals individually and in combination on the biosynthesis and accumulation of secondary metabolites in medicinal plants is discussed in the present review.

The perspectives of using Pelargonium sidoides hybrids

Aim. The Pelargonium sidoides DC. is a valuable medicinal plant, and its irrational use in nature may lead to the species receiving rare status in the future. Obtaining P. sidoides hybrids with a higher content of phenolic compounds will expand the range of plants used in the pharmaceutical industry and reduce the pressure on natural resources. The purpose was to improve methods of growing P. sidoides in greenhouse conditions, obtain hybrids of this species, and research them for the content of various phenolic compounds in vegetative organs. Methods. Light microscopy, spectrophotometry (determination of the total content of phenols and flavonoids, the content of phenolic antioxidants and phenolic acids). Results. The anatomical structure of the leaves and roots of the obtained hybrids did not differ significantly from those of the pure species. It has been found that growing P. sidoides and its hybrids in greenhouse conditions with high summer temperatures increase the synthesis and accumulation of phenolic substances in all vegetative organs. It is important to emphasize that high levels of flavonoids and phenol carboxylic acid have been detected in the leaves, so it is advisable to use them as raw materials for the pharmaceutical industry also. Conclusion. The cultivation methods of the studied plants have been improved. The use of hybrid plants for obtaining flavonoids is more effective for the pharmaceutical industry but less practical in getting other phenolic compounds compared to P. sidoides have been found. The revealed difference in the localization and amount of secondary metabolites indicates the need for a detailed study of other substances of a phenolic nature in the leaves and roots of these pelargoniums.

Polyphenol Characterization of the Aqueous Extract from Hubertia ambavilla L. (Asteraceae) by HPLC-DAD-ESI-MSn and Assessment of Its Antioxidant Activity.

In this work, phytochemical components, and the antioxidant properties of an aqueous extract obtained from a medicinal plant Hubertia ambavilla, endemic to Reunion Island, were investigated. A total of 37 compounds were detected and identified by high-performance liquid chromatography (UHPLC) using a photodiode-array detector (DAD) coupled with electrospray ionization/mass spectrometry (ESI/MSn ). From calibration curves, the quantity of secondary metabolites in the aqueous extract was calculated. The mean amounts of phenols, flavonoids, and condensed tannins found were 158.38±1.20 mg GAE/g DE, 60.41±1.65 mg AE/g DE and 23.77±1.36 mg CE/g DE, respectively. The in vitro antioxidant properties of the Hubertia ambavilla plant were measured using three methods: DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging and ferric reducing antioxidant power. The results showed that crude aqueous extract of H. ambavilla had effective radical scavenging and reducing power in comparison with standard antioxidant compounds. In conclusion, the crude extract herein presented offers a natural alternative biosource of antioxidants with potential applications in food and health industries.

Biologically synthesized CuO nanoparticles induce physiological, metabolic, and molecular changes in the hazel cell cultures.

The utilization of plant extracts in nanoparticle (NP) synthesis has been suggested as a nature-friendly method and an efficient alternative to the conventional approaches such as physical and chemical methods. Taxol is a valuable medicinal compound, and hazelnut has been suggested as one of the sustainable resources for producing this metabolite. In the present research, copper oxide (CuO) nanoparticles (NPs) were biologically synthesized by utilizing hazelnut leaf extracts. FTIR, XRD, EDAX, DLS, and SEM analyses were used for characterizing and confirming the synthesized NPs. The effect of biosynthesized CuO NPs (10 and 90ppm), para-aminobenzoic acid (PABA) (20ppm), and CuSO4 (10ppm) on the cell viability, biochemical properties, expression of TAT and GGPPS genes, and accumulation of taxol and baccatin III in hazelnut cell cultures was investigated. The results indicated that biosynthesized CuO NPs significantly influenced the cell viability, amount of ROS, antioxidant capacity, lipid peroxidation, secondary metabolite production, and expression pattern of the genes engaged in the biosynthesis pathway of taxanes in the C. avellana L. cells. The cytotoxicity of CuO NPs to cells was dose dependent and increased with increasing its concentration, as evidenced by a decline in the survival rate and cell membrane integrity. Furthermore, the utilization of 10ppm CuSO4 caused more toxicity in the cells than the same concentration of CuO NPs. This result could be attributed to the fact that plant extracts components act as a coating for the NPs and reduce their toxicity. Treatment of the cell cultures with CuO (10ppm) + PABA (20ppm) and CuO (10ppm) induced the highest radical scavenging activity. The activity of antioxidant enzymes was increased with increasing the copper oxide NPs level from 10 to 90ppm. Contrariwise, the cell's survival rate, radical scavenging activity, and amount of secondary metabolites were significantly reduced in the higher levels of copper oxide NPs (90ppm) compared to the 10ppm. The combined utilization of 10ppm copper oxide NPs and 20ppm PABA considerably stimulated the TAT and GGPPS genes expression and produced the highest amount of taxol and baccatin III. KEY POINTS: • CuO NPs were biologically synthesized using the hazel leaf extracts and confirmed by FTIR, XRD, EDAX, DLS, and SEM analyses. • CuO NPs significantly affected the amount of ROS, antioxidant capacity, and lipid peroxidation in C. avellana L. cells. • Treatment of the hazel cells with CuO NPs increased the production of secondary metabolites including taxol and baccatin III and expression of thegenes involved in taxol and baccatin III biosynthesis (TAT and GGPPS).

Effect of Different Abiotic Stresses on Allium Cepa Plants: Results from a Field Study of Two Different Seasons

Abiotic factors have the capacity to influence the nature and quantity of secondary metabolites. Alteration of environmental factors during plant growth can affect the production of bioactive phytoconstituents. A six-month field study was carried out in two different seasons to assess the effect of different abiotic stresses on bioactive compounds, i.e. flavonoids and phenols and plant yield of selected Allium species, i.e. Allium cepa L. (AC). (Family Amaryllidaceae). AC plants were grown for six months from November to April and for another six months from May to October on three different soil types (i.e. black, red, clay-loamy) and various stresses (salinity, water deprivation, flooding, fertilizer, metal, shade) were applied on the plants. At the end of the season, plants were collected, dried, and plant yield was determined. Hydroalcoholic extracts of all samples were prepared. Plant yield, TFC, TPC were determined in all the extracts. The results show varied response of AC plants to different soil types, stresses, and seasons. AC plants cultivated on red soil with fertilization give higher biomass yield in both seasons. AC plants grown in black soil under metal stress have highest TFC, TPC. Hence these conditions may be recommended for incorporation in cultivation practices of these valuable medicinal plants to ensure commercial supply of plants with higher phenol and flavonoid content and better plant yield.

Modulated Light Dependence of Growth, Flowering, and the Accumulation of Secondary Metabolites in Chilli.

Chili is widely used as a food additive and a flavouring and colouring agent and also has great importance in health preservation and therapy due to the abundant presence of many bioactive compounds, such as polyphenols, flavonoids, carotenoids, and capsaicinoids. Most of these secondary metabolites are strong antioxidants. In the present study, the effect of light intensity and spectral composition was studied on the growth, flowering, and yield of chilli together with the accumulation of secondary metabolites in the fruit. Two light intensities (300 and 500 μmol m–2 s–1) were applied in different spectral compositions. A broad white LED spectrum with and without FR application and with blue LED supplement was compared to blue and red LED lightings in different (80/20 and 95/5%) blue/red ratios. High light intensity increased the harvest index (fruit yield vs. biomass production) and reduced the flowering time of the plants. The amount of secondary metabolites in the fruit varied both by light intensity and spectral compositions; phenolic content and the radical scavenging activity were stimulated, whereas capsaicin accumulation was suppressed by blue light. The red colour of the fruit (provided by carotenoids) was inversely correlated with the absolute amount of blue, green, and far-red light. Based on the results, a schematic model was created, representing light-dependent metabolic changes in chilli. The results indicated that the accumulation of secondary metabolites could be modified by the adjustment of light intensity and spectral composition; however, different types of metabolites required different light environments.

Evaluation of antimicrobial activity and phytochemical screening of red Kamboja (Plumeria rubra L.) extracts

Natural antimicrobial sources such as red Kamboja (Plumeria rubra L.) flower extract can be utilized to treat infectious disorders caused by Staphylococcus aureus, Escherichia coli, and Candida albicans. This study aims to determine evaluate the effectiveness of methanol and ethanol extracts of P. rubra floral against E. coli, S. aureus, and C. albicans growth, as well as the amount of secondary metabolites in P. rubra extract. The study's findings indicate that the highest DIZ value of P. rubra methanol extract was 7.40 mm, 7.36 mm, and 7.30 mm for S. aureus ATCC25923 at 5%, 10%, and 20%, respectively, while the highest DIZ value for C. albicans ATCC10231 at 10%, 10%, and 20% was 25.08 mm, and 25.04 mm, respectively. The DIZ value of the P. rubra flower ethanol extract against E. coli strain was 5.26 mm at 5%, and 7.30 mm at 20%. Secondary metabolites of saponins, tannins, alkaloids, flavonoids, steroids, and phenols were present in the methanol and ethanol extracts of P. rubra flowers. In summary, our findings highlight the use of P. rubra flower extract as a biological source with antibacterial properties for the control of human infectious illnesses.

Defensive responses of Populus deltoides cl. Beikang to mechanical injury and Anoplophora glabripennis infection.

Poplar, as the main tree species of the protection forest in the "Three-North" area of China, has been seriously damaged by Anoplophora glabripennis since 1970s. Populus deltoides cl. Beikang (PDB) shows strong resistance to A. glabripennis, but the biochemical mechanism of resistance is unclear. In this study, the quantities of secondary metabolites and the activity of defense enzymes in bark and xylem from undamaged, mechanically damaged, and A. glabripennis infected PDB were detected by kit and HPLC techniques. The results showed different responses of PDB to mechanical damage and A. glabripennis infection. Secondary metabolites, the quantities of D-(-)-salicin and aspen significantly increased after mechanical injury compared with the undamaged materials, but the quantities of quercitrin decreased. The quantities of D-(-)-salicin and quercitrin significantly increased after insect infection, but without difference for aspen. There was no significant difference for the total quantities of phenolics between insect infected and uninjured xylem, but both were significantly lower than that in the mechanical damaged xylem. The quantities of aspen and flax lignans in the insect infected xylem was higher than those in the mechanical damaged xylem and uninjured xylem, while the quantities of total phenolic glycosides in the mechanical damaged xylem and the insect infected xylem were both significantly higher than that in the uninjured xylem. PAL activity was not different between mechanical damage and insect infection, whereas both were significantly higher than that of uninjured bark. SOD activity in mechanical damaged bark was significantly higher than that in insect infected bark, which were both higher than that of uninjured bark. POD activity had no significant difference between mechanical damage and insect infected xylem, but were higher than that of uninjured xylem. Compared with the uninjured PDB tree, the secondary metabolites and defense enzymes in the mechanical damaged and A. glabripennis infected PDB increased in varied degrees, which would be related with the resistance of PDB to external injury.

Analysis of Phenotypic Characteristics and Sucrose Metabolism in the Roots of Raphanus sativus L.

The taproot of radish (Raphanus sativus L.) is an important sink organ; it is morphologically diverse and contains large amounts of secondary metabolites. Sucrose metabolism is believed to be important in the development of sink organs. We measured the amounts of glucose, fructose, and sucrose in the roots of sixty three radish accessions and analyzed the association between the sugar content and the root phenotype. Fructose content correlated with the root color and length characteristics, glucose was the most abundant sugar in the roots, and the sucrose content was very low, compared to that of the hexoses in most of the accessions. Expression analysis of the genes involved in sucrose metabolism, transportation, starch synthesis, and cell wall synthesis was performed through RNA sequencing. The genes encoding sucrose synthases (SUSY) and the enzymes involved in the synthesis of cellulose were highly expressed, indicating that SUSY is involved in cell wall synthesis in radish roots. The positive correlation coefficient (R) between the sucrose content and the expression of cell wall invertase and sugar transporter proteins suggest that hexose accumulation could occur through the apoplastic pathway in radish roots. A positive R score was also obtained when comparing the expression of genes encoding SUSY and fructokinase (FK), suggesting that the fructose produced by SUSY is mostly phosphorylated by FK. In addition, we concluded that sucrose was the most metabolized sugar in radish roots.

The Influence of Environmental Conditions on Secondary Metabolites in Medicinal Plants: A Literature Review.

Medicinal plants, a source of different phytochemical compounds, are now subjected to a variety of environmental stresses during their growth and development. Different ecologically limiting factors including temperature, carbon dioxide, lighting, ozone, soil water, soil salinity and soil fertility has significant impact on medicinal plants' physiological and biochemical responses, as well as the secondary metabolic process. Secondary metabolites (SMs) are useful for assessing the quality of therapeutic ingredients and nowadays, these are used as important natural derived drugs such as immune suppressant, antibiotics, anti-diabetic, and anti-cancer. Plants have the ability to synthesize a variety of secondary metabolites to cope with the negative effects of stress. Here, we focus on how individual environmental variables influence the accumulation of plant secondary metabolites. A total of 48 articles were found to be relevant to the review topic during our systematic review. The review showed the influence of different environmental variables on SMs production and accumulation is complex suggesting the relationship are not only species-specific but also related to increases and decline in SMs by up to 50 %. Therefore, this review improves our understanding of plant SMs ability to adapt to key environmental factors. This can aid in the efficient and long-term optimization of cultivation techniques under ambient environmental conditions in order to maximize the quality and quantity of SMs in plants.

Histochemical observations in Piper malgassicum (Piperaceae) with a special focus on the epidermis

This is the first contribution about the histochemistry of vegetative and reproductive aerial organs in the genus Piper L. Piper malgassicum accumulates alkaloids and terpenes in the epidermis and the underlying layers of parenchyma, both in the leaves, in the stems and in anthers. Some idioblasts appear to contain a large amount of secondary metabolites. The micro-anatomical analysis showed peculiar secretory structures both in the leaves, in the anthers and in the ovary. Several lipid aggregates, alkaloid droplets and calcium oxalate crystals were observed in leaves and stems, indicating their role in defence strategies, mechanical support, and pollinators attraction. In the anthers, we observed elaioplasts whose content suggest an alternative and indirect function in pollination and defence against micro-organisms. Besides, some lipid aggregates surrounded by microtubules, detected in the anthers, were recognized as lipotubuloids. The tapetum was of secretory type. Alkaloids and terpenes were widely distributed in the plant confirming the important biological role of this type of biomolecules and its functional range. In the anthers, terpene and polyphenol inclusions appeared particularly abundant in the epidermal layer, whereas calcium oxalate crystals were observed close to the ovule in the ovary at maturity.

Effect of seasonal changes on the quantity of secondary metabolites from neem and eucalyptus plants in North Central Nigeria

Traditional healthcare system depends majorly on natural medicinal plants from the environment. These plants produce secondary metabolites which confer on them the various medicinal properties; however, Seasonal fluctuations have impact on their availability and quantity hence their therapeutic efficacy. This study was carried out to evaluate the effect of seasonal changes on the quantity of secondary metabolites from Neem and Eucalyptus plants. Leaves and bark of Neem and Eucalyptus plants from SHESTCO, Federal Capital Territory (FCT), Abuja, Nigeria, were collected during the four quarters of the year 2019. Samples were dried, milled into powder, quantity of secondary metabolites was estimated and antioxidant activity was analysed using standard methods and protocols. Results from this study showed a variation in secondary metabolite compositions in response to seasons. In both plants’ organs, saponin content peaked and crashed during the second and fourth quarters of the year respectively, while alkaloid had the highest content during the fourth quarter of the year. Highest level of tannin was recorded in the leaf and bark of the plants during the third quarter of the year. Antioxidant activity of both plant extracts showed a regular patterned decrease with increasing concentration, with lowest antioxidant activity for both plants’ organs recorded during the third quarter. Findings of the study indicate that the quantity of inherent secondary metabolites in the medicinal plants and their corresponding antioxidant activity varies in specific manners at different times of the year due to seasonal variation.