Oil fractions of Pistachia lentiscus and their use in the treatment or prevention of oral cavity and ear, nose and throat infections caused by gram-positive or gram-negative bacteria

Description

[0001] The present invention relates to fractions of Pistacia lentiscus edible oil enriched with polyphenols, obtainable by a process comprising ultracentrifugation followed by winterisation of the supernatant, solubilisation in water-alcohol mixtures, sonication and removal of the alcohol-based solvent.

[0002] The fractions according to the invention have bactericidal action against Gram-negative oral pathogenic bacteria, in particular against Moraxella catarrhalis and Haemophilus influenzae.

[0003] The fractions according to the invention produce significant synergic effects when used in combination with antibiotics, in particular with beta-lactam antibiotics, effectively eradicating bacterial infections caused by both Gram-negative bacteria (Moraxella catarrhalis, Haemophilus influenzae) and Gram-positive bacteria (Streptococcus pyogenes and Streptococcus pneumoniae).Prior art

[0004] The current emergency relating to the increasingly widespread antibiotic resistance of many species of pathogenic bacteria poses a serious health problem. In an attempt to extend research designed to solve said problem, the scientific community has focused on new treatment strategies, and recently expressed renewed interest in plant-based compounds (Pogány Simonová M, et al., Res Vet Sci. 2010 Apr;88(2):203-7; Verkaik MJ et al., J Dent. 2011 Mar; 39(3):218-24). The antibiotic potential of most of said derivatives, used for "non-antibiotic" applications, is little known (Reid G. Curr Infect Dis Rep. 2000 Dec;2(6):518-522.). Antibiotic resistance is due (inter alia) to the ability of many bacteria to forma biofilms that provide a protective waterproof coating for antimicrobials. Biofilm formation has been described for various human body tissues, for example in the oral cavity and on the skin (Flemmig TF, Beikler T. Periodontol 2000. 2011 Feb;55(1):9-15; Vieira Colombo AP et al., Microb Pathog. 2016 May;94:27-34).

[0005] One solution to this problem could therefore be the development of active ingredients able to damage the biofilm that protects the bacterial colony. Recent observations (Orrù G, Front Microbiol. 2017 Oct 24;8:2067) demonstrate that the edible oil of the fruit of Pistacia lentiscus, a plant used in traditional medicine (Bozorgi M et al., Scientific World Journal. 2013 Dec 15;2013:219815), exhibits antibacterial activity against Gram-positive bacteria such as Streptococcus agalactiae, Streptococcus intermedius, Streptococcus mitis, Streptococcus mutans and Streptococcus pyogenes. Other authors (Mezni F et al., Nat Prod Res. 2015;29(6):565-70) have reported its antibiotic action against Staphylococcus aureus and its anti-fungal action against Candida spp. and Aspergillus niger. The majority of the research conducted in the past focused on the antimicrobial properties of the inedible part, i.e. the mastic gum and essential oil, obtained from the resin and the branches / leaves respectively. Mastic gum (produced on the Greek island of Chios) possesses proven antibacterial activity against Helicobacter pylori, while the derivatives formulated from the essential oil have proved active against oral pathogens such as Porphyromonas gingivalis, Streptococcus mutans, Streptococcus gordonii, Fusobacterium nucleatum and Prevotella intermedia (Paraschos S et al., Curr Med Chem. 2012;19(14):2292-302; Aksoy A et al., Arch Oral Biol. 2006 Jun;51(6):476-81; Liu W et al., Zhongguo Zhong Yao Za Zhi. 2019 Sep;44(17):3684-3694).

[0006] The medical literature therefore demonstrates that the edible oil is primarily active against Gram-positive species, and only the essential oil, which is inedible, also exhibits some activity against Gram-negative species such as Prevotella and Fusobacterium, which are involved in periodontal disease and gingivitis.

[0007] Healthy oral microbiota (Abranches J et al., Microbiol Spectr. 2018 Oct;6(5)) contain a predominance of Streptococcus salivarius, which can constitute up to 80% of the entire bacterial flora. However, dysbiosis of the oral cavity promotes the growth of pathogenic species liable to cause pharyngotonsillitis and otitis media. The pathogens most frequently involved are Streptococcus pyogenes and Streptococcus pneumoniae (Gram-positive), Moraxella catarrhalis and Haemophilus influenzae (Gram-negative). Edible mastic (or lentisk) oil only performs an antibacterial action against Streptococcus pyogenes, and is wholly ineffective against other species. Moreover, the action of edible mastic oil has no synergic effects when administered simultaneously with antibiotics.

[0008] In view of the absence of a Moraxella vaccine and the aggressive nature of Haemophilus, the only vaccine for which is effective against only one of the six existing serotypes (serotype B), said two Gram-negative species are of great pathological importance, especially in the paediatric field.Description of the invention

[0009] It has now been found that when Pistacia lentiscus edible oil undergoes a process comprising an ultracentrifugation step followed by a supernatant winterisation step, solubilisation in water-alcohol mixtures, preferably water-ethanol mixtures, sonication and removal of the water-alcohol solvent, a fraction enriched in phenol compounds with advantageous antibacterial properties is obtained.

[0010] According to the invention, the ultracentrifugation is preferably conducted at 15,000-20,000 rpm for 10-20 minutes.

[0011] Winterisation is a fractionated crystallisation conducted on edible fats, which is designed to separate a plurality of fractions with different melting points. In the treatment of olive oil, for example, winterisation is conducted during rectification, after deodorising, and consists of fast cooling to a temperature of about 5-10°C, kept constant for several (6-12) hours. The triglycerides with the lowest degree of unsaturation thus crystallise, making separation by filtration possible. The elimination of said substances prevents the oil from clouding at cold temperatures and makes it less viscous. The excess waxes, if any, are separated at the same time.

[0012] According to the invention, the Pistacia lentiscus oil is winterised by treatment at a temperature ranging between -50°C and -90°C, preferably at -80°C, for a time ranging between 24 and 48 hours, preferably 36 hours. The fixed oil derived as supernatant is then mixed with an ethanol / water mixture (75 / 25; v / v). Specifically, 100 g of oil is mixed with 250 ml of water-ethanol solution for 10 minutes in a vortex. The mixture is then isolated in an ultrasonic bath for 30 minutes at room temperature and centrifuged at 15000 rpm for 10 minutes. The water-ethanol phase is then removed by drying, stored in a cold, dark place and mixed again at the ratio of 4:1 with the oil obtained after winterisation. The total polyphenol content of the final fractions thus obtained ranges between 3 and 6% by weight.

[0013] The fractions according to the invention, in the form of a straw-coloured liquid, have an antimicrobial action, which is also observed at ng / mL concentrations, against Moraxella catarrhalis and Haemophilus influenzae.

[0014] The fractions according to the invention are particularly useful in the treatment or prevention of oral cavity infections and ear, nose and throat infections caused by Gram-positive or Gram-negative bacteria, in particular those caused by Moraxella catarrhalis or Haemophilus influenzae.

[0015] The fractions according to the invention are particularly indicated for adjuvant treatment, concomitantly with antibiotic treatment, of pharyngotonsillitis and otitis media, especially if they are resistant to conventional antibiotic treatments.

[0016] It has been observed that the fractions according to the invention produce synergic effects with many conventional antibiotics. Such synergy can be observed in the culture plate, wherein the action of the mastic oil fraction induces the death of 100% of colonies of S. pneumoniae, S. pyogenes, M. catarrhalis and H. influenzae, in the presence of 10, 10, 15 and 20% respectively of the antibiotic required to obtain the same result. Said performance has been demonstrated using amoxicillin and clavulanic acid, amoxicillin alone, and 1st, 2nd, 3rd and 4th generation cephalosporins.

[0017] As observed in BHI-Congo red plates, the action is mediated by total destruction of the biofilms that the Moraxella catarrhalis and Haemophilus influenzae strains can still produce.

[0018] The edible mastic oil fractions thus obtained, hereinafter called "OLUW", can be solubilised as a macerated oil in triglycerides and administered in the form of drops, or formulated after adsorption as chewable tablets or orosoluble sachets.

[0019] The invention is illustrated in detail in the examples below.EXAMPLE 1 - Gum disc

[0020] Compound Quantity OLUW100 µgGum base200 mgLevilite20 mgTalc F.U.20 mgVegetable magnesium stearate18 mgShellac12 mgXylitol250 mgGum Arabic6 mgTitanium dioxide6 mgCarnauba wax0,2 mg EXAMPLE 2 - Orodispersible formulation

[0021] Compound Quantity OLUW100 µgSorbitol160 mgOrange flavouring20 mgMandarin flavouring5 mgAcesulfame K2 mgAerosil5 mgFructose1566 mg Example 3 - Paediatric drops

[0022] Compound Quantity OLUW50 µgEdible triglycerides2,5 mgVitamin E1,5 mgDispersing agent / emulsifierq.s.

Claims

1. Fraction of edible Pistacia lentiscus oil enriched in polyphenols obtainable by ultracentrifugation followed by winterisation of the supernatant, solubilisation in water-alcohol mixtures, preferably water-ethanol mixtures, sonication and removal of the water-alcohol solvent.

2. Fraction according to claim 1 wherein the ultracentrifugation is carried out at 15,000-20,000 rpm for 10-20 minutes.

3. Fraction according to claim 1 or 2, wherein the winterisation is carried out by treatment at a temperature ranging between -50°C and -90°C, preferably at -80°C, for a time ranging between 24 and 48 hours, preferably 36 hours.

4. Fraction according to one of claims 1 to 3 having a polyphenol content ranging between 3 and 6% by weight.

5. Fraction of claims 1-4 for use in the treatment or prevention of oral cavity and ear, nose and throat infections caused by Gram-positive or Gram-negative bacteria.

6. Fraction for use according to claim 5 wherein the infections are caused by Moraxella catarrhalis or Haemophilus influenzae.

7. Fraction for use according to claim 5 or 6 for the prevention of bacterial pharyngotonsillitis and acute otitis media and for the adjuvant treatment, in combination with antibiotic treatment, of pharyngotonsillitis and otitis media, especially if resistant to conventional antibiotic treatments.

8. Process for the preparation of the fractions of claims 1-4 which includes ultracentrifugation of Pistacia lentiscus oil followed by winterisation of the supernatant, solubilisation in water-alcohol mixtures, preferably water-ethanol mixtures, sonication and removal of the water-alcohol solvent.

9. Process according to claim 8 wherein the ultracentrifugation is carried out at 15,000-20,000 rpm for 10-20 minutes and the winterisation is carried out by treatment at a temperature ranging between -50°C and -90°C, preferably at - 80°C, for a time ranging between 24 and 48 hours, preferably 36 hours.