**2. History**

There are more than 300,000 species of plants, ranging from green algae to seed plants. Only a relatively small amount of these plants has been used since human populations were still collectors. With the beginning of agriculture and the expansion of mankind, the number of plants employed as nourishment or for medicinal purpose increased. The use of plants as a way to ease human ailments dates back to prehistory. In some parts of the World the

Antimicrobial Activity of Condiments 113

Worldwide, among the most used and studied spices and condiments known for the proven or supposed antibacterial activity we find aniseed (*Pimpinella anisum*), bay leaf (*Laurus nobilis*), black pepper (*Piper nigrum*), cinnamon (*Cinnamonum verum*), clove (*Syzygium aromaticum*), coriander (*Coriandrum sativum*), garlic (*Allium sativum*), ginger (*Zingiber officinale*), lime (*Citrus aurantifolia*), onion (*Allium cepa*), oregano (*Origanum vulgare*) and thyme (*Thymus vulgaris*). All of these are, generally, widely available in nearly every corner

Apart from the world areas associated with great vegetable diversity, like tropical regions, densely forested areas of South America, sub-Saharian Africa or Southeast Asia, we also can find a great number of plants/herbs with medicinal use. In an academic study made in 2002, in a Portuguese National Park, with a relatively small area, 346 hectare, 140 different plants were found, with 124 different medicinal uses, 15 aromatic, 16 categorized also as condiments

Table 1 lists a number of well-known plants and herbs, many used daily worldwide, and

**Common name Scientific denomination Antimicrobial component** 

and 20 others, including 2 specimens classified as toxic/poisonous (Rodrigues, 2002).

Apple *Malus sylvestris* Phlosetin (flavonoid)

Basil *Ocimum basilicum* Terpenoids Bay *Laurus nobilis* Terpenoids Black pepper *Piper nigrum* Piperine Caraway *Carum carvi* Coumarin Cashew *Anacardium purshiana* Polyphenols Chamomile *Matricaria chamomilla* Phenolic acid Chili peppers *Capsicum annuum* Capsaicin Clove *Syzygium aromaticum* Eugenol Coriander *Coriadrum sativum* -

Dill *Anethum graveolens* Terpenoids Eucalyptus *Eucalyptus globulus* Tannin Fava bean *Vicia faba* Fabatin Garlic *Allium sativum* Allicin Olive *Olea europaea* Hexanal Onion *Allium cepa* Allicin

Rosemary *Rosmarinus officinalis* Terpenoids

Table 1. Plants and herbs and their main antimicrobial components

(adapted from Cowan, 1999).

Peppermint *Mentha piperita* Menthol (terpenoid)

Thyme *Thymus vulgaris* Caffeic acid, thymol, tannins Turmeric *Curcuma longa* Curcumin (terpenoid)

**3. Plants, herbs and condiments** 

their most important antimicrobial component.

Alfalfa *Medicago sativa* - Allspice *Pimenta dioica* Eugenol Aloe *Aloe barbadensis / Aloe vera* Latex

**3.1 Conventional products** 

of the world.

medicinal practices envolving vegetable products, conventionally called ethnomedicine, may not have changed very dramatically since those ancient times, particularly in tribal areas of South American rain forest, Africa or South East Asia. These areas have a common characteristic – an overwhelming diversity and amount of plant material to be used.

There are many historical records on the use of plants for treating ailments ranging from 4.000 B.C. The first medical record filed in the Pennsylvania Museum is dated 2.100 B.C. and includes a collection of thirty different formulas of drugs of plant origin, animal or mineral. The Egyptian manuscript *Ebers Papirus* (1.500 B.C.), contains 811 prescriptions and 700 drug and the first Chinese text on herbal (500 B.C.) reports names, doses and indications for the use of plants to treat disease. Some of these plants are still used, such as ginseng (*Panax* spp.), *Ephedra* spp., *Cassia* spp. and *Rheum palmatum L*., including as sources for pharmaceuticals industries.

Early reports, from various civilizations, mentioned several medicinal plants and their effects. The Greek physician Hippochrates (V century B.C.) described 300 to 400 medicinal plants and their effects. Another Greek physician Pedanius Dioscorides (I century A.D.) wrote a catalog of medicinal plants with the Latin title "De Materia Medica", in what is nowadays considered to be one of the world's first pharmacopeias. Even religious documents, as the Christian Bible, indicated some products of vegetable origin with antiseptic properties, namely frankincense and myrrh that were used in Ancient Middle East (including Ancient Egypt) as mouthwashes. In imperial China, we assisted the discovery of tea and other infusions described as having soothing properties and other medicinal characteristics.

As time went by and Man began accumulating more knowledge, critical analysis and observation of results began to follow the true scientific method. The real therapeutic success of many of these plants was mixed. In some cases, cure was achieved or symptoms were truely relieved. Other plants have shown to be only ideal for nutricional purposes. The more dramatic cases were of plants being simply considered source of poisoning.

Since the advent of antibiotics, in the 1920's, following Alexander Fleming's findings, researchers focused in microorganisms to obtain new ways to kill other microorganisms. The development of microbial resistance as well as economic incentives triggered the research and development of new antibiotics in order to maintain a pool of effective drugs in all situations. Although the development of resistant strains is inevitable, the way we manage and use antibiotics has exacerbated the process. The growing emergence of resistance phenomenon led to new classes of antibiotics of synthetic origin. Unfortunately, the rate of new and more efficient antibiotics is not as fast as microorganisms finding new ways to survive. Thus, in the beginning of the 21st century we assist to a race to plants, trying to discover innovative natural weapons to fight infectious diseases and microbial contaminations in food.

Since medicinal plants produce a variety of substances with antimicrobial properties, it is expected that screening programs discover candidate compounds for the development of new antibiotics. However, scientific research to determine the therapeutic potential of plants is limited, there is a lack of scientific studies that confirm the possible experimental antibiotic properties of a large number of these plants. It is expected that compounds that reach targets different from those used by known antibiotics may be active against resistant pathogens.

medicinal practices envolving vegetable products, conventionally called ethnomedicine, may not have changed very dramatically since those ancient times, particularly in tribal areas of South American rain forest, Africa or South East Asia. These areas have a common

There are many historical records on the use of plants for treating ailments ranging from 4.000 B.C. The first medical record filed in the Pennsylvania Museum is dated 2.100 B.C. and includes a collection of thirty different formulas of drugs of plant origin, animal or mineral. The Egyptian manuscript *Ebers Papirus* (1.500 B.C.), contains 811 prescriptions and 700 drug and the first Chinese text on herbal (500 B.C.) reports names, doses and indications for the use of plants to treat disease. Some of these plants are still used, such as ginseng (*Panax* spp.), *Ephedra* spp., *Cassia* spp. and *Rheum palmatum L*., including as sources for

Early reports, from various civilizations, mentioned several medicinal plants and their effects. The Greek physician Hippochrates (V century B.C.) described 300 to 400 medicinal plants and their effects. Another Greek physician Pedanius Dioscorides (I century A.D.) wrote a catalog of medicinal plants with the Latin title "De Materia Medica", in what is nowadays considered to be one of the world's first pharmacopeias. Even religious documents, as the Christian Bible, indicated some products of vegetable origin with antiseptic properties, namely frankincense and myrrh that were used in Ancient Middle East (including Ancient Egypt) as mouthwashes. In imperial China, we assisted the discovery of tea and other infusions described as having soothing properties and other

As time went by and Man began accumulating more knowledge, critical analysis and observation of results began to follow the true scientific method. The real therapeutic success of many of these plants was mixed. In some cases, cure was achieved or symptoms were truely relieved. Other plants have shown to be only ideal for nutricional purposes. The

Since the advent of antibiotics, in the 1920's, following Alexander Fleming's findings, researchers focused in microorganisms to obtain new ways to kill other microorganisms. The development of microbial resistance as well as economic incentives triggered the research and development of new antibiotics in order to maintain a pool of effective drugs in all situations. Although the development of resistant strains is inevitable, the way we manage and use antibiotics has exacerbated the process. The growing emergence of resistance phenomenon led to new classes of antibiotics of synthetic origin. Unfortunately, the rate of new and more efficient antibiotics is not as fast as microorganisms finding new ways to survive. Thus, in the beginning of the 21st century we assist to a race to plants, trying to discover innovative natural weapons to fight infectious diseases and microbial

Since medicinal plants produce a variety of substances with antimicrobial properties, it is expected that screening programs discover candidate compounds for the development of new antibiotics. However, scientific research to determine the therapeutic potential of plants is limited, there is a lack of scientific studies that confirm the possible experimental antibiotic properties of a large number of these plants. It is expected that compounds that reach targets different from those used by known antibiotics may be active against resistant

more dramatic cases were of plants being simply considered source of poisoning.

characteristic – an overwhelming diversity and amount of plant material to be used.

pharmaceuticals industries.

medicinal characteristics.

contaminations in food.

pathogens.
