Chemical Composition, Antibacterial Activity, and Antibiotic Potentiation of Boswellia sacra Flueck. Oleoresin Extracts from the Dhofar Region of Oman.

Luay Rashan,Ian Edwin Cock,Parag Das,Nicolas Favelin,Alan White,Manon Haulet,Elia Ranzato

doi:10.1155/2021/9918935

Abstract

The emergence of MDR bacterial pathogens has directed antibiotic discovery research towards alternative therapies and traditional medicines. Boswellia sacra oleoresin (frankincense) was used to treat bacterial infections in traditional Arabian and Asian healing systems for at least 1000 years. Despite this, B. sacra extracts have not been rigorously tested for inhibitory activity against gastrointestinal pathogens or bacterial triggers of autoimmune diseases. Solvent extracts were prepared from Boswellia sacra oleoresins obtained from three regions near Salalah, Oman. MIC values were quantified against gastrointestinal pathogens and bacterial triggers of selected autoimmune diseases by disc diffusion and broth dilution methods. The antibacterial activity was also evaluated in combination with conventional antibiotics, and the class of interaction was determined by ΣFIC analysis. Isobolograms were used to determine the optimal ratios for synergistic combinations. Toxicity was evaluated by ALA and HDF cell viability bioassays. The phytochemical composition of the volatile components of all extracts was identified by nontargeted GC-MS headspace analysis. All methanolic extracts inhibited the growth of all of the bacteria tested, although the extracts prepared using Najdi oleoresin were generally more potent than the Sahli and Houjari extracts. Combinations of the methanolic B. sacra extracts and conventional antibiotics were significantly more effective in inhibiting the growth of several bacterial pathogens. In total, there were 38 synergistic and 166 additive combinations. Approximately half of the synergistic combinations contained tetracycline. All B. sacra extracts were nontoxic in the ALA and HDF cell viability assays. Nonbiased GC-MS headspace analysis of the methanolic extracts putatively identified a high diversity of monoterpenoids, with particularly high abundances of α-pinene. The antibacterial activity and lack of toxicity of the B. sacra extracts indicate their potential in the treatment and prevention of gastrointestinal and autoimmune diseases. Furthermore, the extracts potentiated the activity of several conventional antibiotics, indicating that they may contain resistance-modifying compounds.

Highlights

Introduction e World Health Organisation (WHO) considers antibiotic-resistant bacteria to be one of the most urgent issues facing medical science [1]. e development of widespread antibiotic-resistant strains of many common bacterial pathogens in recent years has reduced the efficacy of many clinical antibiotics and in many cases has rendered common clinical antibiotics of little or no use to combat infections
Only minor differences in phytochemical profiles were noted between the three B. sacra cultivars and between the three different extraction methods
All extracts were generally devoid of all other classes of phytochemicals, or they were below the detection threshold

Summary

Introduction

Introduction e World HealthOrganisation (WHO) considers antibiotic-resistant bacteria to be one of the most urgent issues facing medical science [1]. e development of widespread antibiotic-resistant strains of many common bacterial pathogens in recent years has reduced the efficacy of many clinical antibiotics and in many cases has rendered common clinical antibiotics of little or no use to combat infections.is trend is expected to increase in future years with the transfer of resistance genes between strains of the same bacterial species and between species. Some strains are totally drug resistant (TDR) to all common clinical antibiotics and there are few effective treatment modalities to treat these infections. Ere is a lack of effective treatments against that strain, and given the highly infectious nature of M. tuberculosis and the high mortality of the active form of the disease, tuberculosis has the potential to cause substantial + loss of life in future years. This disease has the potential to cause substantially greater mortality than the current COVID-19 pandemic and new antibiotic therapies against this (and other MDR pathogens) are urgently needed

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