Bergamot: characteristics of the plant, fruit, flavanones and hypocholesterolemic properties

Introduction to Bergamot  

Bergamot (Citrus bergamia ) is a citrus fruit known for its aromatic and medicinal properties, belonging to the Rutaceae family , mainly widespread in Calabria, Italy. This fruit is renowned for its essential oil used in perfumery and for its cholesterol-lowering properties . In this article we will explore its complex botanical origin, the characteristics of the plant, the properties of flavonoids and its role in reducing cholesterol.  

 

Taxonomy and Nomenclature of the Citrus Genus  

The taxonomy and nomenclature of the genus Citrus (family Rutaceae ) are complex and continually evolving with modern molecular biology techniques. The classification of citrus species is difficult to define, considering the large number of interspecific hybrids and cultivars. Flavonoids present in citrus fruits, including bergamot , are important not only for their aromatic value, but also for their medicinal properties, which include positive effects on cholesterol.  

 

Origins of Bergamot  

 

The difficulties in precisely defining the phylogeny of bergamot , i.e. its genetic and geographical origins, are linked to the complexity of its study. Bergamot (Figure 1) is an interspecific hybrid that derives from the crossing of different citrus species: Citrus x aurantium (bitter orange), Citrus x limon (lemon), Citrus x aurantifolia (lime), or even from Citrus medica (citron), as confirmed by recent studies ( Valussi et al., 2021).  

 

Figure 1. Botanical table of bergamot ( from Köhler , HA Köhler's Medizinal-Pflanzen . Arch. Pharm . 1887, 225, 276 ) .    

 

According to some sources, bergamot originated in Calabria or, more generally, in southern Italy . Other theories suggest that bergamot originated outside Italy, in the Antilles , Greece or the Canary Islands , and that it was then introduced to Calabria between the 14th and 16th centuries, where today about 90% of the world's bergamot is produced. Some claim that the fruit was brought to Italy by Christopher Columbus through the Spanish city of Berga in Catalonia , which would have inspired the name of bergamot.  

However, the most plausible hypothesis is that the name bergamot derives from the Turkish ' beg -a-mudi ' or ' beg armudu ', which means 'pear of the Prince' or 'pear of the Lord', referring to the shape and importance of the fruit (Dugo and Bonaccorsi, 2013).  

There are also disagreements among taxonomists regarding the correct scientific name, as reported in Table 1 .  

 

Table 1. Nomenclature of bergamot according to different institutions and authorities in the field of taxonomy (taken from Valussi et al., 2021) .  

Authority/institution  

Binomial nomenclature  

Integrated Taxonomic Information System  

Citrus aurantium subsp. bergamia (Risso & Poit .) Wight & Arn. ex Eng l .  

International Plant Names Index  

Citrus bergamia Risso  

Tropics  

Citrus × bergamot Rice & Poit .  

World Checklist of Selected Plant Families  

Citrus limon (L.) Osbeck  

US Department of Agriculture: Agricultural Research Service  

Citrus × limon (L.) Osbeck var. bergamia (Loisel.) uned .  

Mabberley's Plant Book  

Citrus × limon , Bergamot group  

 

Some authors identify four subgroups of bergamot , different based on the morphology of the plant and the fruit, as well as the flavour and aroma of the latter :  

  • Small  

  • Torulous  

  • Applerose  

  • Common  

 

This last group is the most important from an industrial point of view and includes the cultivars 'Castagnaro', 'Femminiello' and 'Fantastico' (or 'Inserto'), the latter, in turn, a more recent hybrid (obtained around 1940) between the first two cultivars ( Dugo and Bonaccorsi, 2013 ) .  

 

Agronomic description of Bergamot  

From an agronomic and botanical point of view , the bergamot tree is grafted onto bitter orange rootstock and pruned to 4-5 meters in height, with a leaf cover of about 5 meters in diameter. The bergamot has large, alternate leaves, similar to those of the lemon in color and shape. The flowers, white and characterized by an unmistakable scent, sprout at the beginning of spring (between March and April). The bergamot fruit is a modified berry called hesperidium, with a pear-shaped shape, with a weight that varies between 80 g and 200 g. The outer peel of the bergamot has a variable thickness and can be smooth or wrinkled. The peel is divided into a thin, colored exocarp, called flavedo, and a deeper mesocarp called albedo.  

The fruit contains the juicy part of the bergamot, namely the endocarp, with pulp ranging in color from green to pale yellow, with an acidic and bitter taste. Bergamot fruits can be harvested between December and February, when they reach maturity. During maturation, the flavedo develops cavities called lacunae , which fill with essential oil , which can be extracted by cold pressing (Rapisarda et al., 1996; Fatta Del Bosco et al., 2020).  

In Calabria , which produces about 90% of the world's bergamot, cultivation takes place on about 1400 hectares, along the coastal strip of Reggio from Villa San Giovanni to Monasterace , on the Ionian Sea. This area is protected from the north winds by the Aspromonte , and the ideal climatic conditions – with average temperatures among the highest in Italy and the absence of frost – make it possible to grow high-quality bergamot (Amato et al., 2013; Nesci et al., 2014).  

From a nutritional point of view, bergamot is rich in vitamins , mineral salts and bioactive phytochemical compounds, with recognized health properties. Bergamot juice is particularly rich in flavonoids , such as neoeriocitrin , neohesperidin , naringin , and rutin , known for their biological activities, including hypocholesterolemic ( Adorisio et al., 2023).  

Flavonoids, secondary metabolites derived from phenylalanine and malonyl CoA, are divided into several groups, with flavanones being particularly representative in bergamot juice. These compounds have shown positive health effects, contributing to cardiovascular and metabolic well-being ( Adorisio et al., 2023).  

The most representative flavonoids in bergamot juice are :  

  • Neoeriocitrin  

  • Neohesperidin  

  • N herringin a  

  • R u tin a  

  • Neodesmin a  

  • R oifolin a  

  • poncirin a  

(Figure 2).  

 

Figure 2. Chemical structure, molecular formula and molecular weight (MW) of the main flavonoids present in bergamot juice .  

 

The studies  

Systemic inflammation and hypercholesterolemia are recognized as crucial risk factors for the development and progression of cardiovascular diseases, including atherosclerosis. Numerous clinical studies have demonstrated the efficacy of flavanones present in bergamot juice in controlling dyslipidemia and improving the lipid profile.  

In a study conducted on 80 subjects with moderate hypercholesterolemia, a bergamot extract containing 150 mg of flavonoids, including neoeriocitrin , neohesperidin and naringin , was administered . After 6 months of treatment, a significant reduction in total cholesterol, LDL and triglycerides was observed, with an increase in HDL cholesterol. In addition, an improvement in carotid arterial wall thickness was found, suggesting that supplementation with bergamot polyphenols may reduce plasma lipids and improve the lipoprotein profile in subjects with moderate hyperlipidemia (Toth et al., 2016).  

Another study analyzed the effect of a bergamot-based supplement on subjects with moderate hypercholesterolemia. The intake led to a reduction in C-reactive protein levels, improving parameters of systemic inflammation and endothelial reactivity (Fogacci et al., 2022). Previously, a study had shown that bergamot extract reduced TNF-α levels in overweight subjects with dyslipidemia (Cicero et al., 2019).  

In a further study, the lipid-lowering effect of a bergamot-based product, BrumexTM , was observed, which reduced the cholesterol and triglyceride content in HepG2 cells in vitro. A subsequent clinical trial confirmed these results, showing significant improvements in the lipid and lipoprotein profile of participants, including reductions in total cholesterol, LDL, triglycerides and fasting blood glucose levels (Pierdomenico et al., 2023).  

Furthermore, a pilot study documented the bioavailability of flavanones from bergamot juice, identifying several plasma and urinary metabolites, including sulfates and glucuronides of hesperidin , naringenin , and eriodictyol . Some of these metabolites showed anti-inflammatory activity, reducing the gene expression of inflammatory markers such as IL-1b, IL-6, IL-8, and TNF-α (Spigoni et al., 2017).  

These results suggest that bergamot, thanks to its flavonoids and other bioactive components, could represent a valid support in the management of dyslipidemia and inflammation, with potential benefits for cardiovascular health.  

The cholesterol-lowering properties of bergamot juice are summarized in Table 2 .  

 

Table 2. Effects of bergamot on dyslipidemia : clinical studies  

Bergamot based product  

Pathological condition/ experimental model  

Biomarkers  

Bibliographic references  

Brumex TM  

Patients with moderate hypercholesterolemia  

Total cholesterol, triglycerides, LDL cholesterol, non-HDL cholesterol, apolipoprotein B100, fasting blood glucose, glutamic- oxaloacetic transaminase , glutamate-pyruvate transaminase , gamma- glutamyl -transferase  

Pierdomenico et al., 2023  

Nutraceutical product containing bergamot extract 

Patients with moderate hypercholesterolemia  

High sensitivity C-reactive protein , endothelial reactivity  

Fogacci et al., 2022  

Extract Of bergamot 

Overweight patients with dyslipidemia  

High-sensitivity C-reactive protein , TNF- α  

Cicero et al., 2019  

Bergamot extract 

Patients with moderate hypercholesterolemia  

Total cholesterol, LDL cholesterol, triglycerides, HDL cholesterol, intima-media thickness of the carotid arterial wall  

Toth et al., 2016  

 

Bibliography  

Adorisio S, Muscari I, Fierabracci A, Thi Thuy T, Marchetti MC, Ayroldi E, Delfino DV. Biological effects of bergamot and its potential therapeutic use as an anti-inflammatory, antioxidant, and anticancer agent. Pharm Biol . 2023 Dec;61(1):639-646.  

Amato, A.; Castellotti, T.; Gaudio, F.; Gaudio, G.; Lovecchio, R.; Pupo D'Andrea, MR; Peluso, R. Agriculture in Calabria in numbers 2012; INEA–National Institute of Agricultural Economics: Rome, Italy , 2013. Accessible online: http://www.inea.it/pubbl/ .  

Calabrese, F. The Fabulous History of Citrus Fruits; The Epos: Palermo, Italy , 1998 .  

Cicero, A.F.G.; Fogacci , F.; Bove, M.; Giovannini, M.; Borghi, C. Three-arm, placebo-controlled, randomized clinical trial evaluating the metabolic effect of a combined nutraceutical containing a bergamot standardized flavonoid extract in dyslipidemic overweight subjects. Phytotherapy Res. 2019 , 33 , 2094–2101.  

Dosoky , N.S.; Setzer, W.N. Biological Activities and Safety of Citrus spp. Essential Oils. Int. J. Mol. Sci. 2018, 19, 1966.  

Dugo, G.; Bonaccorsi, I. Citrus Bergamia: Bergamot and its Derivatives; CRC Press: Boca Raton, FL, USA, 2013.  

Fatta Del Bosco, S.; Abbate, L.; Mercati, F.; Napoli, E.; Ruberto, G. Essential Oils in Citrus. In The Citrus Genome; Gentile, A., La Malfa, S., Deng, Z., Eds.; Springer International Publishing: Cham, Switzerland, 2020; pp. 211–223 .  

Fogacci , F.; Rizzoli, E.; Giovannini, M.; Bove, M.; D'Addato , S.; Borghi, C.; Cicero, AFG Effect of Dietary Supplementation with Eufortyn ® Cholesterol Plus on Serum Lipids, Endothelial Reactivity, Indexes of Non-Alcoholic Fatty Liver Disease and Systemic Inflammation in Healthy Subjects with Polygenic Hypercholesterolemia: The ANEMONE Study. Nutrients 2022, 14, 2099.  

English, P.; Sortino, G. Citrus History, Taxonomy, Breeding, and Fruit Quality. In Oxford Research Encyclopedia of Environmental Science; Oxford University Press: Oxford, UK, 2019; ISBN 9780199389414.  

Nesci, FS; Sapone, N. Bergamot–A Green and Multifunctional Asset Exclusive from the Province of Reggio Calabria. AEF 2014, 11, 376–379.  

Pierdomenico, M., Cicero, A.F., Veronesi, M., Fogacci, F., Riccioni, C., & Benassi, B. (2023). Effect of Citrus bergamia extract on lipid profile: A combined in vitro and human study. Phytotherapy Research , 37(9), 4185-4195.  

Rapisarda, A.; Caruso, C.; Iauk , L.; Ragusa, S. Application of image analysis in the study of the oil glands of fruits of some species of the Citrus genus. Deriv Essences Citrus . 1996, 66, 5–12.  

Spigoni, V., Mena, P., Fantuzzi, F., Tassotti, M., Brighenti, F., Bonadonna, RC, ... & Dei Cas, A. (2017). Bioavailability of bergamot (Citrus bergamia) flavanones and biological activity of their circulating metabolites in human pro-angiogenic cells. Nutrients , 9(12), 1328.  

Toth, P.P., Patti, A.M., Nikolic, D., Giglio, R.V., Castellino, G., Biancucci, T., ... & Rizzo, M. (2016). Bergamot reduces plasma lipids, atherogenic small dense LDL, and subclinical atherosclerosis in subjects with moderate hypercholesterolemia: a 6 - month prospective study. Frontiers in Pharmacology, 6, 299.  

Valussi , M.; Donelli, D.; Firenzuoli , F.; Antonelli, M. Bergamot Oil: Botany, Production, Pharmacology. Encyclopedia 2021, 1, 152–176.  

Wu, G.A.; Terol, J.; Ibanez, V.; López-García, A.; Pérez-Román, E.; Borredá , C.; Domingo, C.; Tadeo, F.R.; Carbonell-Caballero, J.; Alonso, R.; et al. Genomics of the origin and evolution of Citrus. Nature 2018, 554, 311–316 .  

Zhong, G.; Nicolosi, E. Citrus Origin, Diffusion, and Economic Importance. In The Citrus Genome; Gentile, A., La Malfa, S., Deng, Z., Eds.; Springer International Publishing: Cham, Switzerland, 2020; pp. 5–21.