Phytochemical profiling and antimicrobial activity of Morinda pubescens Fruit

Introduction

Due to the availability of certain bioactive components that are used by the pharmaceutical industry, plants are utilized as medicine in a variety of cultures and are a source of powerful pharmaceuticals. Different phytochemicals, sometimes referred to as secondary metabolites, are found in plants. Because of their unique, complementary, or synergistic effects on health, phytochemicals can be helpful in the treatment of specific illnesses. In the pharmaceutical sector, phytochemicals are essential for the creation of new medications and therapeutic agents. The plant known as Morinda pubescens or Morinda coria was found by J.E. Smith and belongs to the Rubiaceae family. It is widely distributed throughout Southern Asia, showing a complete migration from the western to the eastern slopes of the Ghats, and it is primarily found in the dry regions of Southern Deccan and Southern Travancore.

Morinda pubescens plant was selected for the study (Figure 1). The Morinda pubescens was collected from the village Ralegan Siddhi, Tahsil Parner, Ahmednagar, Maharashtra, India. The plant was authenticated as Morinda pubescens (Family: Rubiaceae) by the Botanical Survey of India, Western Regional Centre.

Drying and Pulverizing

After obtaining the Morinda pubescens, they were dried for four weeks in the shade. To prevent microbiological contamination, ongoing monitoring was done. To create a fine powder, the dried plant materials were extracted and processed. To get even smaller particles, the powder was passed through a 2 mm sieve once more. Until they were required for the investigation, the powdered samples were kept in a clean glass container at a low temperature.

Extraction of Plant Material Aqueous Extract

Morinda pubescens was dried, ground, and placed in a 250 g sample container. The sample was macerated in water for seven days. Following that, the marc was removed by filtering, and then the marc was pressed. The solvent was evaporated using a rotating solvent evaporator. In the end, the extract was weighed, and its proportion of the plant material's air-dried weight was determined.

Hydroalcoholic Extract

Morinda pubescens fruit was dried, ground, and placed in a 250 g sample container. The sample was macerated in a water-ethanol mixture (6:4) for seven days. Following that, the marc was removed by filtering, and then the marc was pressed. The solvent was evaporated using a rotating solvent evaporator. In the end, the extract was weighed, and its proportion of the plant material's air-dried weight was determined [11] .

Chloroform Extract

Morinda pubescens fruit was dried, ground, and placed in a 250 g sample container. The sample was macerated in chloroform for seven days. Following that, the marc was removed by filtering, and then the marc was pressed. The solvent was evaporated using a rotating solvent evaporator. In the end, the extract was weighed, and its proportion of the plant material's air-dried weight was determined.

Butanol Extract

Morinda pubescens fruit was dried, ground, and placed in a 250 g sample container. The sample was macerated in ethanol for seven days. Following that, the marc was removed by filtering, and then the marc was pressed. The solvent was evaporated using a rotating solvent evaporator. In the end, the extract was weighed, and its proportion of the plant material's air-dried weight was determined [12] .

Phytochemical Screening of Extract

The Morinda pubescens fruit extract was observed for the identification of various phytoconstituents by carrying out phytochemical tests.

Screening of Antimicrobial Activity of Morinda pubescens Extracts

The antimicrobial activity of Morinda pubescens aqueous, hydroalcoholic, chloroform, and butanol extracts was tested using bacterial strains E. coli and S. aureus. The pour plate assay was used. By autoclaving at 120°C (15 psi), the medium was made sterile. The zone of inhibition was checked for Morinda pubescens extract [13] .

Sample Preparation

The lyophilized powder was made soluble in n-hexane and ethanol, and the GC-MS analysis of the compounds was performed. 1.0 g of the lyophilized powdered Morinda pubescens was soaked in 10 ml of ethanol and n-hexane separately for 12 hours. The extract was vortexed and filtered. 1.0 μl of this filtered solution was injected for GC-MS analysis.

Mass Spectrometry-Gas Chromatography (GC-MS) Analysis

GC-MS analysis of the extract of Morinda pubescens fruit was performed using a Thermo Scientific TRACE Ultra Gas Chromatograph interfaced to a TSQ Quantum Ultra™ Triple Quadrupole Mass Spectrometer (GC-MS) equipped with Trace GOLD TG-5MS GC Columns (5% diphenyl, 95% dimethylpolysiloxane) fused capillary column (30 × 0.25 μm ID × 0.25 μm df).

Helium (99.999%) was used as the carrier gas with a flow rate of 1 ml/min. The splitless mode was used. An aliquot of 1 μl of the sample solution was injected into the column. The oven temperature was programmed from 80 °C (isothermal for 0.0 min), with an increase of 5.0 °C/min, to 300 °C, ending with an isothermal hold at 300°C for 2.0 min. The injector and auxiliary temperatures were set at 300 °C and 280 °C, respectively. The ion source temperature was maintained at 225 °C. The mass spectrum of compounds in the samples was obtained by electron ionization at 70 eV, and the detector was operated in scan mode from 35-500 m/z. The total running time was 46 minutes. The relative percentage amount of each component was calculated by comparing its average peak area to the total peak areas [14] .

Identification of Compounds

The National Institute of Standards and Technology (NIST) database was used to analyze the mass spectra and identify the components based on their retention indices. The database contains more than 62,000 patterns of recognized compounds. The standard mass spectra of known components stored in the NIST library (NIST II) were compared to the acquired spectra of the unknown components in the Morinda pubescens fruit fraction. 1).

Results and Discussion

Preliminary Antimicrobial Activity of Morinda pubescens Extract

The antimicrobial activity of Morinda pubescens fruit extract was evaluated. Different extracts of Morinda pubescens fruit were tested for antimicrobial activity using the pour plate method. The diameter of the zone of inhibition against various Gram-positive and Gram-negative bacteria was found to be 20 mm for E. coli and 16 mm for S. aureus.

The results indicate that all extracts of Morinda pubescens fruit have antimicrobial activity.

GC-MS Analysis

The GC-MS chromatogram of the standardized extract of Morinda pubescens fruit (Figure 2) showed various major peaks, indicating the presence of different phytochemical constituents.

On comparison of the mass spectra of the constituents with the NIST library, the different phytocompounds were characterized and identified. The spectrum of the unknown component was compared with the spectrum of the component stored in the NIST library, and the results are tabulated.

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