Marcel Proust (1871–1922) ascribed his ability to resurrect the past in his writing to ‘involuntary memory’, whereby, for example, after dipping a piece of madeleine cake into some tea, the ‘shaken partitions in my memory gave way’ under the influence of taste and smell as he recalled Aunt Léonie (Carter, 2000). Aroma, memory, and emotion are intertwined, and readers of a certain age might associate pine with childhood visits to hospitals whose well-ventilated corridors and waiting areas were often disinfected with forest-scented cleaning products that were occasionally swamped with pungent chlorine-tinged antiseptics
Considered the largest genus of conifers, Pinus (Pinaceae) includes more than 100 different species (Dziedziński et al, 2021), and Hickman (2021) explains that the creation of the town of Bournemouth, Dorset, stemmed partly from the apparent health-giving properties of its pine trees. Hickman (2021) further notes that while the Edward VII Sanatorium in Midhurst, Sussex – opened in 1906 – confirmed ‘[t]he choice of pine forests as the ideal and scientifically sanctioned location for sanatoria in Britain …’, the role of pine trees in disinfecting the air later declined, and ‘with the development of successful pharmaceutical and surgical treatments including antibiotics for tuberculosis, the pine forest gradually lost its therapeutic significance’ (Hickman, 2021).
However, citing the health-promoting properties of plant polyphenols – including their anti-inflammatory, anti-allergic, anti-atherosclerotic, anticoagulant and antimutagenic effects – Dziedziński et al (2021) highlight ‘pine tree preparations on the market, which are concentrated sources of polyphenols. The most popular pine tree preparation is an extract from P. pinaster – Pycnogenol®’, and the first documented use of pine bark extracts dates from 1535, when French explorer Jacques Cartier and his crew avoided scurvy – from vitamin C deficiency – by drinking pine bark brew (Dziedziński et al, 2021).
Yet a systematic review by the Cochrane Collaboration (Robertson et al, 2020) that evaluated 27 randomised controlled trials (RCTs) on the effects of supplements containing pine bark extracts on ten different chronic diseases, provided little support for its effectiveness. Thus, after considering pine bark extract RCTs on asthma, attention deficit hyperactivity disorder, cardiovascular disease, chronic venous insufficiency, diabetes, erectile dysfunction, female sexual dysfunction, osteoarthritis, osteopenia and traumatic brain injury, Robertson et al (2020) concluded: ‘Small sample sizes, limited numbers of RCTs per condition, variation in outcome measures, and poor reporting of the included RCTs mean no definitive conclusions regarding the efficacy or safety of pine bark extract supplements are possible’ (Robertson, 2020). This conclusion, however, is challenged by Dziedziński et al (2021) who argue that the review did not consider ‘many other studies, including particularly interesting research on skin health and protection … Furthermore, the role of antioxidants from the pine extracts in neuroprotective activity may prove to be fundamental, as P. radiata bark extracts exhibited effectiveness in two cases of RCT.’
From pine bark to pine tar – the result of pinewood carbonisation following distillation using extreme heat – which has been used in medicine for more than 2000 years to treat a range of skin conditions because of its soothing and antiseptic properties (Barnes and Greive, 2017). Pine tar has been shown to be anti-pruritic, anti-inflammatory, anti-bacterial and anti-fungal, and probably exerts its effect by reducing DNA synthesis and mitotic activity, which promotes normal keratinisation, making it suitable for the topical treatment of eczema, psoriasis, seborrhoeic dermatitis and similar dry, itchy, or inflamed skin conditions (Barnes and Greive, 2017).
In the context of COVID-19, the avoidance of which we are told can be helped by well-ventilated buildings, today's hospitals – compared to yesteryear – exist in an atmosphere of ‘olfactory neutrality’, as Hickman (2021) puts it, ‘unlike the open-air sanatorium in the pine forest which, with its open windows and balconies, shared the same sense-scape in as well as out as air moved freely across the threshold.’ The first open-air orthopaedic hospital was set up in the Shropshire village of Baschurch in 1907, and in 1915, the Master of Christ's College, Cambridge A.E.
Shipley (1861–1927), pronounced the open-air treatment of sick and wounded soldiers at Cambridge's First Eastern General Hospital a success (Hobday and Cason, 2009).
With an impressive evidence base for the therapeutic virtues of a versatile conifer, allied to ventilation, one pines for a scented zephyr of fresh air through a hospital ward, waiting room… or pharmacy.