Can Ocimum basilicum L. and Ocimum tenuiflorum L. in vitro culture be a potential source of secondary metabolites?

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.

Development of an allele-specific PCR (AS-PCR) method for identifying high-methyl eugenol-containing purple Tulsi (Ocimum tenuiflorum L.) in market samples

BACKGROUND

Ocimum tenuiflorum L. is a highly traded medicinal with several therapeutic values. Green Tulsi and purple Tulsi are two subtypes in O. tenuiflorum and both have the same medicinal properties. Recent reports have revealed that purple Tulsi contains higher quantities of methyl eugenol (ME), which is moderately toxic and potentially carcinogenic. Therefore, we developed an allele-specific PCR (AS-PCR) method to distinguish the green and purple Tulsi.

METHODS AND RESULT

Using the green Tulsi as a reference, 12 single nucleotide polymorphisms (SNPs) and 10 insertions/deletions (InDels) were identified in the chloroplast genome of the purple Tulsi. The C > T SNP at the 1,26,029 position in the ycf1 gene was selected for the development of the AS-PCR method. The primers were designed to amplify 521 bp and 291 bp fragments specific to green and purple Tulsi, respectively. This AS-PCR method was validated in 10 accessions from each subtype and subsequently verified using Sanger sequencing. Subsequently, 30 Tulsi powder samples collected from the market were subjected to molecular identification by AS-PCR. The results showed that 80% of the samples were purple Tulsi, and only 3.5% were green Tulsi. About 10% of the samples were a mixture of both green and purple Tulsi. Two samples (6.5%) did not contain O. tenuiflorum and were identified as O. gratissimum.

CONCLUSION

The market samples of Tulsi were predominantly derived from purple Tulsi. The AS-PCR method will be helpful for quality control and market surveillance of Tulsi herbal powders.

Comprehensive Metabolomic Fingerprinting Combined with Chemometrics Identifies Species- and Variety-Specific Variation of Medicinal Herbs: An Ocimum Study

Identification of plant species is a crucial process in natural products. Ocimum, often referred to as the queen of herbs, is one of the most versatile and globally used medicinal herbs for various health benefits due to it having a wide variety of pharmacological activities. Despite there being significant global demand for this medicinal herb, rapid and comprehensive metabolomic fingerprinting approaches for species- and variety-specific classification are limited. In this study, metabolomic fingerprinting of five Ocimum species (Ocimum basilicum L., Ocimum sanctum L., Ocimum africanum Lour., Ocimum kilimandscharicum Gurke., and Hybrid Tulsi) and their varieties was performed using LC-MS, GC-MS, and the rapid fingerprinting approach FT-NIR combined with chemometrics. The aim was to distinguish the species- and variety-specific variation with a view toward developing a quality assessment of Ocimum species. Discrimination of species and varieties was achieved using principal component analysis (PCA), partial least squares discriminate analysis (PLS-DA), data-driven soft independent modelling of class analogy (DD-SIMCA), random forest, and K-nearest neighbours with specificity of 98% and sensitivity of 99%. Phenolics and flavonoids were found to be major contributing markers for species-specific variation. The present study established comprehensive metabolomic fingerprinting consisting of rapid screening and confirmatory approaches as a highly efficient means to identify the species and variety of Ocimum, being able to be applied for the quality assessment of other natural medicinal herbs.

A glance at the chemodiversity of Ocimum species: Trends, implications, and strategies for the quality and yield improvement of essential oil

Ocimum species represent commercially important medicinal and aromatic plants. The essential oil biosynthesized by Ocimum species is enriched with specialized metabolites specifically, terpenoids and phenylpropanoids. Interestingly, various Ocimum species are known to exhibit diverse chemical profiles, and this chemical diversity has been at the center of many studies to identify commercially important chemotypes. Here, we present various chemotypes from the Ocimum species and emphasize trends, implications, and strategies for the quality and yield improvement of essential oil. Globally, many Ocimum species have been analyzed for their essential oil composition in over 50 countries. Asia represents the highest number of chemotypes, followed by Africa, South America, and Europe. Ocimum basilicum L. has been the most widespread and well-studied species, followed by O. gratissimum L., O. tenuiflorum L., O. canum Sims, O. americanum and O. kilimandscharicum Gürke. Moreover, various molecular reasons, benefits, adverse health effects and mechanisms behind this vast chemodiversity have been discussed. Different strategies of plant breeding, metabolic engineering, transgenic, and tissue-culture, along with anatomical modifications, are surveyed to enhance specific chemotypic profiles and essential oil yield in numerous Ocimum species. Consequently, chemical characterization of the essential oil obtained from Ocimum species has become indispensable for its proper utilization. The present chemodiversity knowledge from Ocimum species will help to exploit various applications in the industrial, agriculture, biopharmaceutical, and food sectors.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-021-09767-z.

In Vitro Assessment of the Interaction Potential of Ocimum basilicum (L.) Extracts on CYP2B6, 3A4, and Rifampicin Metabolism

Ocimum basilicum L. or basilicum is a common culinary herb, used as a traditional medicine for various medical conditions including HIV/AIDS and tuberculosis, in Africa. The objective of this study was to evaluate the effect of methanol, ethanol, aqueous and ethyl acetate extracts of the dried leaves and inflorescence of O. basilicum, on the activity of cytochrome P450 enzymes (CYPs) CYP2B6 and 3A4, as well as esterase-mediated metabolism of rifampicin to 25-O-desacetyl rifampicin (25ODESRIF). Human liver microsomes (HLM) were used to evaluate inhibition and CYP2B6/3A4 mRNA expression HepG2 assays were used to measure induction. Furthermore, the phytoconstituents likely involved in causing the observed effect were analyzed using biochemical tests and LC-MS. The aqueous and methanolic extracts showed reversible and time-dependent inhibition (TDI) of CYP2B6 with TDI-IC₅₀s 33.35 μg/ml (IC₅₀ shift-fold >1.5) and 4.93 μg/ml (IC₅₀ shift-fold >7) respectively, while the methanolic and ethanolic extracts inhibited 25ODESRIF formation (IC₅₀s 31 μg/ml, 8.94 μg/ml). In HepG2 assays, the methanolic and ethanolic extracts moderately induced CYP2B6, 3A4 mRNA with 38%-, 28%-fold shift, and 22%-, 44%-fold shift respectively. LC-MS full scans identified phenols rosmarinic acid [m/z 359 (M-H)^-, approximately 2298 mg/L in aqueous extract] and caftaric acid along with flavones salvigenin [m/z 329 (M+H)⁺, approximately 1855 mg/L in ethanolic extract], eupatorin [m/z 345 (M+H)⁺, 668.772 mg/L in ethanolic extract], rutin [m/z 609 (M-H)^-] and isoquercetin [m/z 463 (M-H)^-] and other compounds—linalool [m/z 153 (M-H)^-], hydroxyjasmonic acid [m/z 225 (M-H)^-], eucommiol [m/z 187 (M-H)^-] and trihydroxy octadecenoic acid [m/z 329 (M-H)^-, 530 mg/L in ethanolic extract]. The putative gastrointestinal tract (GIT) concentration for all extracts was calculated as 2,400 μg/ml and hepatic circulation concentrations were estimated at 805.68 μg/ml for the aqueous extract, and 226.56 μg/ml for methanolic extract. Based on the putative GIT concentration, estimated hepatic circulation concentration [I] and inhibition constant K_i, the predicted percentile of inhibition in vivo was highest for the aqueous extract on CYP2B6 (96.7%). The observations indicated that O. basilicum extracts may have the potential to cause clinically relevant herb-drug interactions (HDI) with CYP2B6 and rifampicin metabolism in vivo, if sufficient hepatic concentrations are reached in humans.

A Systematic Review on Synthetic Drugs and Phytopharmaceuticals Used to Manage Diabetes

BACKGROUND

Diabetes is a multifactorial disease and a major cause for many microvascular and macrovascular complications. The disease will ultimately lead to high rate mortality if it is not managed properly. Treatment of diabetes without any side effects has always remained a major challenge for health care practitioners.

INTRODUCTION

The current review discusses the various conventional drugs, herbal drugs, combination therapy and the use of nutraceuticals for the effective management of diabetes mellitus. The biotechnological aspects of various antidiabetic drugs are also discussed.

METHODS

Structured search of bibliographic databases for previously published peer-reviewed research papers was explored and data was sorted in terms of various approaches that are used for the treatment of diabetes.

RESULTS

More than 170 papers including both research and review articles, were included in this review in order to produce a comprehensive and easily understandable article. A series of herbal and synthetic drugs have been discussed along with their current status of treatment in terms of dose, mechanism of action and possible side effects. The article also focuses on combination therapies containing synthetic as well as herbal drugs to treat the disease. The role of pre and probiotics in the management of diabetes is also highlighted.

CONCLUSION

Oral antihyperglycemics which are used to treat diabetes can cause many adverse effects and if given in combination, can lead to drug-drug interactions. The combination of various phytochemicals with synthetic drugs can overcome the challenge faced by the synthetic drug treatment. Herbal and nutraceuticals therapy and the use of probiotics and prebiotics are a more holistic therapy due to their natural origin and traditional use.

Parasitoids diversity in organic Sweet Pepper (Capsicum annuum) associated with Basil (Ocimum basilicum) and Marigold (Tagetes erecta )

The sweet pepper (Capsicum annuum L.) is one of the most important crops in Brazilian farming. Many insect are related to this crop, compromising the quantity and quality of the fruit, representing a production problem. Vegetable diversification is one of the main elements that can be managed for suppressing undesirable insect populations in organic production, once that supports the presence of natural enemies. The basil Ocimum basilicum L. and the marigold Tagetes erecta L. are attractive and nutritious plants for parasitoids, being important candidates for diversified crops. This study evaluated the parasitoids attracted by the association of basil and marigold to organic sweet pepper crop. The experiment comprised three treatments: a) sweet pepper monoculture; b) sweet pepper and basil intercropping; c) sweet pepper and marigold intercropping. Hymenopteran parasitoids were collected over 14 weeks. 268 individuals from 12 families and 41 taxa were collected. Sweet pepper monoculture, sweet pepper-basil intercropping, and sweet pepper-marigold intercropping hosted 40, 98, and 130 individuals and richness of 24, 24, and 23, respectively. Furthermore, the insects of greater abundance in the basil and marigold were different to those collected in the monoculture. The number of parasitoids increased in the associations of sweet pepper with basil and marigold, providing advantages in the use of vegetable diversification for the organic pepper crops management.

Influence of water stress and storage time on preservation of the fresh volatile profile of three basil genotypes

The main goal of the present study was to describe the volatile profile of three different basil genotypes (Genovese and Green and Purple Iranian), and the impact that water stress (75% and 50% field capacity) and storage time (up to 7days) have under mild refrigerated conditions. The chromatographic profile pointed to three different chemotypes: linalool/eugenol, neral/geranial, and estragol, for Genovese, Green, and Purple genotypes, respectively. Water stress depleted the volatile profile of these three landraces, due to a reduction in the absolute concentrations of some of the components related to fresh aroma (linalool, nerol, geraniol and eugenol). The stability of the basil volatile profile during storage varied depending on the water stress that had been applied. Concentration reductions of close to 50% were quantified for most of the components identified in the Purple genotype.

Inhibitory effect of leaves extracts of Ocimum basilicum and Ocimum gratissimum on two key enzymes involved in obesity and hypertension in vitro

Aim:

To evaluate the phenolics composition and inhibitory effect of the leaves extracts of Ocimum basilicum and Ocimum gratissimum on two key enzymes (pancreatic lipase [PL] and angiotensin 1-converting enzyme [ACE]) involved in obesity and hypertension in vitro.

Materials and Methods:

The phenolics (flavonoids and phenolic acids) were quantified using high-performance liquid chromatography coupled with diode array detection. PL and ACE inhibitory effects; DPPH* and ABTS*⁺ scavenging activities of the extracts were tested using spectrophotometric methods.

Results:

O. basilicum had the following major phenolics: Rutin, quercetin, and quercitrin (flavonoids); caffeic, chlorogenic, and gallic acids (phenolic acids); while O. gratissimum had the following major phenolics: Rutin, quercitrin, and luteolin (flavonoids); ellagic and chlorogenic acids (phenolic acids). “Extracts of both plants inhibited PL and ACE; scavenged DPPH* in a dose-dependent manner”. O. gratissimum extract was more potent in inhibiting PL (IC_50: 20.69 µg/mL) and ACE (IC_50: 29.44 µg/mL) than O. basilicum (IC_50: 52.14 µg/mL and IC_50: 64.99 µg/mL, against PL and ACE, respectively). O. gratissimum also scavenged DPPH* and ABTS*⁺ more than O. basilicum.

Conclusion:

O. basilicum and O. gratissimum leaves could be used as functional foods for the management of obesity and obesity-related hypertension. However, O. gratissimum may be more effective than O. basilicum.