Bioactive Hemp Clothing Modified with Cannabidiol (CBD) Cannabis sativa L. Extract

Abstract

1. Introduction

Cannabis sativa L. is a plant highly appreciated due to its strong ecological features and potential for multidirectional application. The importance of hemp has increased especially nowadays where climate change and environmental degradation are serious problems for our globe. The European Green Deal launched as Europe’s growth strategy aims to make the economy more sustainable, resource-efficient, and competitive, focusing on ensuring: no net emissions of greenhouse gases by 2050, economic growth decoupled from resource use, no person and no place left behind [1]. Hemp fits into the European Green Deal priority particularly in terms of striving to climatic neutrality in 2050. Hemp cultivation and processing cover low-carbon solution idea, 1 ha of one season of hemp growing can absorb about 10 t of CO₂ from the atmosphere, depending on plant variety. Hemp is resistant to drought, its growth does not need watering or too many pesticides, as opposed to cotton. Hemp is a model example of cascading wasteless use of biomass, which is presented in a simplified way in Figure 1. Each part of the plant is raw material suitable to use in different sectors of the economy bringing benefits to farmers and industries. The hemp value chain covers wasteless processing of biomass to produce biodegradable and recyclable products. The diversity of hemp products and their quantitative share in the market is shown in Figure 2.

Currently, the huge interest in hemp is also addressed to textiles. Hemp fiber was traditionally used for technical textiles, mainly for ropes due to its high mechanical properties. The effort of researchers and stakeholders are focused on the development of high quality fiber for textile purpose especially clothing for which the inherent bioactive properties of hemp fibers is added value. Hemp fibers are more difficult to processing in comparison to flax, they are more stiff and coarse. Raw hemp fibers show antibacterial and antioxidant properties resulted from fiber chemical composition, they contain phenolic acids known as natural antioxidants [2]. The antibacterial activity of raw hemp fibers is illustrated in Figure 3, where strains of the bacteria Staphylococcus aureus are located directly on the surface of pure hemp fiber.

Figure 3

Dew retted hemp fibers activity towards Staphylococcus aureus bacteria, the killed bacterias take the form of orange particles. The strains of the clinical Staphylococcus aureus bacteria were isolated from ill people after 90 min of incubation.

However, hemp technological processing can cause the removal of some amount of phenolic acids from the structure of the fiber resulting in a reduction of their bioactivity. Especially the retting process of hemp straw has a significant effect on fiber functionality. The earlier study proved that fibers extracted from the straw with the use of dew retting show the highest bioactivity in comparison to water retted fibers [2]. Hemp fiber bioactivity was found also in the case of use of mechanical extraction from the straw, e.g., decortication without retting process, but such fibers are coarse and contain a high amount of impurities that make them not suitable for the textile purpose.

The challenge of the development of hemp clothing technological chain allowing to keep fiber properties on the acceptable level was taken up in the current study. Additionally CBD extracted from industrial hemp plant panicles was applied on the fabric surface to strengthen the antioxidant and antibacterial activity of the clothing.

Cannabidiol (CBD) is one of at least 85 active cannabinoids identified within the Cannabis plant. Cannabidiol is a phytocannabinoid derived from Cannabis species, which is devoid of psychoactive activity, with analgesic, anti-inflammatory, antineoplastic and chemopreventive activities. Figure 4 illustrates the conversion of cannabigerolic acid (CBGA) into cannabidiol acid (CBDA) that takes place in hemp plants and the next transformation to cannabidiol (CBD) in the laboratory.

CBD is obtained from the top part of hemp, e.g., from plant panicles. Main processing steps to convert hemp biomass into high purity distillate covers trim and flowers collection, extraction with crude oil, removing of fats by winterization, activation with decarboxylation, and purification by distillation, the chain is schematically showed in Figure 5.

Many researchers have studied CBD’s effect on human health, several research papers report the benefits of CBD for the skin, including combating inflammation [4,5,6], pain [7], and melanoma; acting as an analgesic to promote wound healing [8].

In human trials, Palmieri et al. found that topical application of CBD improved skin lesions in the course of psoriasis, e.g., reduction of Psoriasis Area Severity Index, atopic eczema, and tissue scarring, as well as increased skin hydration and elasticity [9]. Likewise, Wilkinson showed that CBD acts on psoriasis in cultured human epidermal keratinocytes [10].

The positive effect of CBD on the human body was approved in many scientific articles, which provided high quality evidence for the neurological effect of cannabidiol in people [11,12,13,14].

However, in 2019, the European Commission announced that CBD and other cannabinoids were classified as “novel foods”, and products containing CBD must be approved as a novel food by a national food authority [15,16]. In December 2020, the European Commission concluded that CBD should not be considered a drug and can be qualified as food [17].

From an EU law perspective, CBD may be used in cosmetics placed on the EU market when obtained from cannabis, cannabis resin, cannabis extracts, and cannabis tinctures originating from the seeds and leaves that are not accompanied by the fruiting tops of the cannabis plant. Cannabidiol is listed in the EU Cosmetics Ingredient Database [18]. Regulation (EU) No 1223/2009 (the Cosmetics Regulation) defines a cosmetic product as any substance or mixture intended to be placed in contact with external parts of the human body for cleaning, perfuming, changing its appearance, protecting, keeping in good condition or correcting body odors [19].

Growing usage of cannabis for medical and recreational purposes, coupled with the holistic benefits of CBD-infused skincare products, is the key growth enabler for the market. The beauty and personal care industry is observing an alteration towards CBD-infused skincare products [20]. These product lines comprise hand care, lip moisturizer, and skincare products.

The global CBD skincare market was valued at USD 551.57 million in 2019 and is expected to reach USD 3168.44 million by 2028, growing at a CAGR of 21.44% during the forecast period, Figure 6 [20]. However, so far, there is a lack of data about the use of cannabidiol for functional textile purposes.

The positive effect of CBD on human skin has been proved by many researchers. Palmieri et al. showed based on skin evaluations (hydration, TEWL, elasticity), clinical questionnaires, and supported by photographic data and investigators’ clinical assessment that topical treatment with CBD-enriched ointment significantly improved the skin parameters, the symptoms, and also the PASI index score. No irritant or allergic reactions were documented during the period of treatment. The topical administration of CBD ointment, without any THC, is a safe and effective non-invasive alternative for improving the quality of life in patients with some skin disorders, especially on inflammatory backgrounds [9]. Results of research conducted by A. Olah et al. proved that CBD had universal sebostatic activity, which was accompanied by substantial anti-inflammatory effects on human skin and would be very much desired in the clinical treatment of acne vulgaris [5]. CBD normalized the pathologically elevated lipogenesis induced by “pro-acne” agents, both quantitatively and qualitatively, suppressed cell proliferation, and prevented the actions of TLR activation or “pro-acne” agents to elevate proinflammatory cytokine levels (universal anti-inflammatory effect).

CBD was shown to inhibit the proliferation of hyperproliferative keratinocytes [10] and it was demonstrated to possess remarkable antibacterial activity [21].

Cannabinoids have been found to have antioxidant properties, unrelated to NMDA receptor antagonism. This newfound property makes cannabinoids useful in the treatment and prophylaxis of a wide variety of oxidation-associated diseases, such as ischemic, age-related, inflammatory, and autoimmune diseases [22].

Knowing the bioactivity of hemp fibers and the influence of cannabidiol CBD extracted from hemp plants on human skin, the goal of this study was defined. The aim was to design of hemp fiber value chain to manufacture functional clothing, using hemp inherent biological activity reinforced by cannabidiol (CBD) applied on the fabric surface. To confirm the developed pure hemp fiber/CBD clothing effect on human skin, human wearing trials were conducted. The functional clothing made of hemp fibers and hemp CBD extract is an innovative solution with a high impact on both human health and wellbeing as well as environmental preservation. The use of cannabinoids to improve the biological activity of hemp textiles has not been reported in any scientific articles published so far. In literature, it is possible to find consideration about functional clothing, including cosmetotextiles improving skin moisture or showing antibacterial, antiaging deodorant and other activity, where the function is given by use of microcapsules or special finishing processes [23,24,25], but there is no data about functional hemp clothing enriched by CBD extract. This invention has been applied for a patent, No: P.438388, 2021.

2. Results and Discussion

The objective of the study was to develop bioactive clothing with the use of only pure hemp components, e.g., hemp fibers modified by Cannabidiol (CBD) extracted from industrial hemp panicles, and to assess its effect on the human skin.

The textile raw material, e.g., hemp fibers extracted from the Bialobrzeskie variety after dew retting was evaluated in terms of fiber parameters and chemical composition. Characteristics of the fibers are presented in Table 1 and Table 2.

The technological parameters of hemp fibers proved their suitability for use in a flax spinning system for textile product purposes. The linear density at the level 0.9 tex means that technical bundles were dividing efficiently on smaller fiber complexes, thanks to applied processes: dew retting and mechanical scutching.

Hemp fibers contained lignin, cellulose, hemicellulose, pectin, waxes, and fats in their chemical composition, Table 2. The value of cellulose content, 68.4% is lower in comparison to flax (71%) and significantly lower in comparison to cotton, where cellulose is about 98% [26,27]. Cellulose and hemicellulose affect the softness of the fibers making the technological processes easier, fibers can be easily straightened out and parallelly laid in fibers stream to form slivers, roving, and then yarn. Pectin glutted elementary fibers into bundles in the plant stem, but most of it was removed during the retting and scutching process. Waxes and fats content affects fiber friction ratio, its low value means the necessity to apply surface natural fats and waxes on the fiber during the technological processes. Lignin content influences fiber stiffness and makes difficulties in the spinning processes. On the other side, lignin is associated with phenolic acids in plants, in the crosslinking between lignin and hemicellulose in the cell wall carbohydrates [28,29,30,31]. Lignin content is correlated with active phenolic acids content in the bast fiber [2].

In the current study, the hemp fibers were extracted from the stem with the use of the dew retting process, where naturally occurring fungi affected by moisture and ambient temperature conditions were responsible for the disintegration of the fibrous plant stem to release fibers [32,33]. The enzymes secreted by fungi can support the antibacterial activity of dew retted fibers. This phenomenon is very limited in the case of the water-retting process because in that case activity of anaerobic bacteria is mainly responsible for fiber release. For this reason, the dew retting was selected to apply in this experiment.

Obtained long hemp fiber with linear density 0.9 tex allowed for the production of yarn with linear mass 85 tex produced with the use of the wet spinning system. The yarn parameters are presented in Table 3. The number of twists and mechanical properties of the hemp yarn were suitable for the weaving process.

2.1. Hemp Fabric and Modification with CBD Extract

Two types of hemp fabric were produced: one with plain and the second with twill weave to give small diversification of raw materials for clothing designers. Twill fabric was characterized with bigger softness, higher air permeability, higher thermal and water vapor resistance in comparison to plain fabric, which resulted from threads setting in fabric structure.

Characteristics of manufactured fabric are presented in Table 4.

Table 4

Properties of pure hemp fabrics.

	Fabric Parameters		Unit	Mean/Standard Deviation (SD)	Plain Weave Fabric	Twill Weave Fabric
Fabric structure	Mass per square meter		g/m2	Mean	267	271
				SD	0.6	3.4
	Threads density l/dm	warp	–	Mean	153	155
				SD	0.5	0.7
		weft		Mean	141	144
				SD	0.5	0.5
Comfort parameters	Hygroscopicity	65% relative humidity of air	%	Mean	7.70	7.92
				SD	0.22	0.13
		100% relative humidity of air		Mean	12.78	12.81
				SD	0.39	0.14
	Water sorption		s	Mean	9	4
				SD	1.8	0.6
	Air permeability		mm/s	Mean	607	822
				SD	23	21
	Thermal resistance		m2 C/w	Mean	0.0307	0.0527
				SD	0.0003	0.0009
	Water vapour resistance		m2 Pa/W	Mean	5.5765	10.6560
				SD	0.1865	0.0257
	UPF		–	Mean	35	25
Mechanical properties	Breaking force	warp	N	Mean	748.48	779.66
				SD	33.98	22.81
		weft		Mean	871.50	762.58
				SD	45.82	41.00
	Elongation in breaking force	warp	%	Mean	16.81	7.68
				SD	0.90	0.59
		weft		Mean	14,07	14,84
				SD	0.31	0.29
	Bending stiffness	warp	m N cm	Mean	15.48	21.50
				SD	1.20	1.33
		weft		Mean	14.14	9.11
				SD	1.29	0.82
	Angle of recovery	Warp right side	O	Mean	71	74
				SD	5.3	5.4
		Warp left side		Mean	75	76
				SD	6.0	6.2
		Weft right side		Mean	68	82
				SD	8.8	5.7
		Weft left side		Mean	83	88
				SD	5.0	7.3
	Abrasion resistance		number of cycles		18,000	10,000

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Results of hemp fabric parameters tests like hygroscopicity, ability to water sorption, air permeability, thermal and water vapor resistance indicated, that clothing made of this fabric will guarantee the comfort of wearing in the condition of everyday life. Additionally, the value of ultraviolet protection factor (UPF) means, that the hemp clothing will protect the user against UV radiation [34]. On the other side, mechanical parameters indicated good resistance to breakage and abrasion, which allowed predicting a long time of clothing use. The ability to use the clothing for a long time results as a consequence in limitation of creation of waste and is one of the tools of waste management necessary for environment protection. Value of bedding stiffness and angle recovery indicated the tendency of the fabric to crease, these features are typical for bast fiber woven materials.

The pure hemp fabric was evaluated in terms of phenolic acids content, the results are presented in Table 5. The phenolic compounds are listed in the literature as antibacterial and antioxidant agents occurring in many different plants [35,36].

Table 5

Phenolic acids content in a pure hemp fabric.

Content of Acids in Hemp Fabric:
Syringic (mg/100 g)		p-Coumaric (mg/100 g)		Ferulic (mg/100 g)
Result	SD	Result	SD	Result	SD
0.178	0.008	0.013	0.000	0.645	0.007

In the current study, the results of the HPLC tests confirmed the presence of p-coumaric, syringic, and ferulic acid in the chemical composition of the hemp fibers in the fabric. It is well established that the presence of syringic acid is correlated with high antioxidant and antibacterial activity [37]. P-Coumaric acid is mainly a plant metabolite that exhibits antioxidant and anti-inflammatory properties. Its bactericidal activity mechanism consists in damaging bacterial cell membrane and interacting with bacterial DNA [38,39]. Ferulic acid is a component of a primary cell wall and is bonded with lignin and hemicellulose in fibrous plants [40]. Strong antioxidant properties of the ferulic acid cause that is used, apart from other applications, as a cosmetic ingredient to protect the skin against unfavorable effects of the environment and to act as an antiaging agent [41,42]. The proven phenolic acids present in the hemp fiber structure resulted in the bioactivity of developed fabric, particularly its antioxidant properties.

The values of the FRAP tests shown in Table 6 confirmed the antioxidant activity of the hemp fabric, which is in line with earlier studies and findings available in the scientific literature [2].

Table 6

Antioxidant activity of pure hemp fabric assessed by the FRAP method.

	Sample Concentration (mg/mL)	FRAP (μmol/L)	Mean FRAP (μmol/L)	SD
Hemp fabric	0.378	22.87	23.04	0.17
		23.04
		23.21
	0.756	41.24	39.59	2.91
		41.34
		36.21
	1.513	83.40	73.99	11.62
		77.58
		61.00
	2.269	120.33	111.21	7.93
		105.97
		107.34
	3.025	151.45	149.80	14.86
		134.18
		163.76

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The developed pure hemp fabric having direct contact with the skin of the clothing wearer will protect the human skin against harmful factors of the environment like free radicals or UV rays thanks to fiber antioxidant activity. The fabric was safe for users, the test of cytotoxicity proved not to be cytotoxic to keratinocytes as it did not influence its proliferation in the cytotoxic examination. Tested material showed slight antibiotic activity (Table 7), in the case of pure hemp fabric, it is a favorable feature for humans in their everyday life and this is added value of the functional clothing.

Table 7

Bioactivity, e.g., antibiotic units (JA), minimal inhibitory concentration (MIC), and cytotoxicity of hemp fabric.

Cytotoxicity (%)	MIC (mg/mL)	JA/g
No toxic effect	240	4.2

To strengthen the fabric bioactivity and to build a bigger potential of clothing to act as cosmetics, extracts from panicles of Cannabis sativa L., e.g., cannabidiol were applied on the material surface. CBD extract in the form of microcapsules was addressed to the textile target. The chemical structure of CBD is shown in Figure 7.

Figure 7

CBD structure.

Microcapsules with CBD extract were commercially purchased from Devan company. In the experiment, the microcapsules were applied on the fabric surface with the use of a suspension concentration of 5 g/m² by the padding method. The microcapsules were bonded to the hemp fabric surface by use of a mix of agents, including a cross-linker specially developed for the thermic process to permit the covalent bonding of microcapsules directly to textile fibers.

The clothing was design to ensure direct continuous contact of active fabric surface with the largest part of human skin, e.g., with long sleeves and long trousers. This guarantees that Cannabidiol presents on the fabric surface is absorbed by skin-supporting neutralization of reactive oxygen spaces and acting as body cosmetic. The example of functional clothing is shown in Figure 8.

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Figure 8

Hemp clothing functionalized by CBD extract.

The microcapsules with CBD were applied to the fabric to give hemp clothing stronger functionality in terms of skincare.

The hemp clothing with microcapsules on its surface was evaluated in terms of the wearing and washing fastness. The test results indicated, that after 6 weeks of clothing use and 20 cycles of washing with the application of gentle process without detergents, most of the microcapsules were present on the fabric surface.

3. Material and Methods

4. Conclusions

Results of the study proved the possibility to produce advanced hemp textiles, where only natural hemp components have been used.

Application of microcapsules to hemp fabric ensures the functionality of clothing resulted from hybrid bioactivity created by combining two active pure hemp components: CBD and fibers processed according to strong technological restrictions.

The developed clothing improves the hydration and lubrication of the skin, helps to keep the proper moisture and gloss of the skin, and enhancing the skin barrier function. The hemp fabric used for the clothing proved to be safe and comfortable, nor irritant or allergen for the skin. The hemp clothing enriched by Cannabidiol shows a high impact not only on the human skin but also on the environment.

The presented solution indicated a new possible direction of clothing technologies development, which are in agreement with principles of The European Green Deal strategy. Production of raw materials, beginning from hemp cultivation allows keeping biodiversity in agriculture, which is important for the protection of the ecosystem, reduction of water and pesticides consumption if compared to cotton, absorbing CO₂ from the atmosphere, and supports a wasteless bioeconomy.

Author Contributions

M.Z. concept, design, and management of the study, comprehensive results analysis and discussion, writing the manuscript; M.P. performed the human trials experiment, contribution in manuscript writing; B.R. performed a part of the experiment; A.G. performed tests of antioxidant activity and phenolic acids content in hemp products; E.K. performed physicomechanical tests; P.P. the physicomechanical and chemical tests. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Ministry of Agriculture and Rural Development of the Republic of Poland within Multiannual Programme: Revitalization and Sustainable development of processing and production of natural fibrous raw materials for needs of agriculture and economy, 2017–2020.

Institutional Review Board Statement

The study was approved by the Bioethics Committee of the Poznan University of Medical Sciences (352/20, 14 May 2020).

Informed Consent Statement

Written informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data presented in this study are available on request from the corresponding author. The data are not publicly available due to protection of patent application.

Conflicts of Interest

The authors declare no conflict of interest.

Footnotes

References